Alpha-mannosidase

Other Names

1,2-alpha-D-mannosidase1,2-alpha-mannosidase1,2-α-D-mannosidase1,2-α-mannosidaseacid alpha-mannosidaseacidic alpha-mannosidasealpha-1,2-mannosidasealpha-1,3-mannosidasealpha-1,4-mannosidasealpha-1,6-mannosidasealpha-D-mannopyranosidasealpha-D-mannosidasealpha-D-mannoside mannohydrolaseEC 3.2.1.24ER-alpha-mannosidaseexo-alpha-mannosidaseexo-α-mannosidaseGolgi alpha-mannosidase IIGolgi alpha-mannosidase IIblysosomal acid alpha-mannosidaselysosomal alpha-D-mannosidaselysosomal alpha-mannosidasemannanasemannosidase Imannosidase IIp-nitrophenyl-alpha-mannosidasep-nitrophenyl-α-mannosidaseα-D-mannopyranosidaseα-D-mannosidaseα-D-mannoside mannohydrolaseα-mannosidase

Synopsis

Alpha-Mannosidase: A Comprehensive Encyclopedic Reference

1. Identity, Nomenclature, and Classification

Alpha-mannosidase (EC 3.2.1.24), also referred to as α-D-mannosidase, p-nitrophenyl-α-mannosidase, α-D-mannopyranosidase, 1,2-α-mannosidase, 1,2-α-D-mannosidase, and exo-α-mannosidase, is an enzyme involved in the cleavage of the α form of mannose. Its systematic name is α-D-mannoside mannohydrolase.

Lysosomal α-mannosidases are class II mannosidases that belong to glycoside hydrolase family 38 (GH38) and play an important role in the degradation of asparagine-linked carbohydrates of glycoproteins. Alpha-mannosidase is an exo-glycosidase and an zinc metalloenzyme. It cleaves alpha-mannosidic linkages from the non-reducing end of N-linked oligosaccharides.

Two broad families of enzymes have been identified that cleave terminal mannose linkages from Asn-linked oligosaccharides, including the Class 1 mannosidases (CAZy GH family 47) of the early secretory pathway involved in the processing of N-glycans and quality control, and the Class 2 mannosidases (CAZy family GH38) involved in glycoprotein biosynthesis or catabolism.

1.1 Human Isoenzymes

Humans express three α-mannosidase isoenzymes. These are distributed across distinct subcellular compartments: lysosomal, Golgi-resident, and cytosolic forms. Lysosomal alpha-mannosidases are soluble and involved in degradation of N-glycans, while endoplasmic reticulum (ER) and Golgi alpha-mannosidases are involved in processing of newly synthesized N-glycans. An additional alpha-mannosidase, Man2C1, is involved in the processing of free oligosaccharides that are formed in the cytosol; its activity is enhanced by Co²⁺, typical of other known cytosolic alpha-mannosidases, and down-regulation of Man2C1 drastically changes the amount and structure of oligosaccharides accumulating in the cytosol.

Two structurally related members of the lysosomal mannosidase family — the broad substrate specificity enzyme human lysosomal α-mannosidase (hLM, MAN2B1) and the human core α-1,6-specific mannosidase (hEpman, MAN2B2) — act in a complementary fashion to effect glycan degradation; besides showing distinct substrate specificity, hEpman has only 28% sequence identity with hLM.

1.2 Common Name and CAS Number

Alpha-mannosidase is registered under several synonymous designations including α-mannosidase, α-D-mannosidase, p-nitrophenyl-α-mannosidase, α-D-mannopyranosidase, 1,2-α-mannosidase, exo-α-mannosidase (EC 3.2.1.24; CAS 9025-42-7).

2. Natural Sources

2.1 Plant Sources

Alpha-mannosidase (EC 3.2.1.24) is a vacuolar enzyme which occurs abundantly in the cotyledons of the jack-bean (Canavalia ensiformis). This plant origin of alpha-mannosidase is historically the most important for research and biochemical applications. Jack bean (Canavalia ensiformis) seeds contain several biologically important proteins among which α-mannosidase (EC 3.2.1.24) has been purified, its biochemical properties studied, and widely used in glycan analysis.

Alpha-mannosyl transfer enzymes are derived from plants such as jack beans (Canavalia ensiformis) or almonds (Prunus amygdalus), enzymes derived from animals such as turban shells (Turbo cornutus) or livers (bovine, rat, human), as well as enzymes derived from microorganisms such as Arthrobacter aurescence and Aspergillus niger.

2.2 Animal and Microbial Sources

Alpha-mannosidase is an acid hydrolase located in plant vacuoles and is thought to be involved with the turnover of N-linked glycoproteins. In mammals, lysosomal alpha-mannosidase is found broadly across tissues. Multiple classical biochemical studies have characterised alpha-mannosidase from Homo sapiens liver, rat liver and epididymis, hog kidney, and hen oviduct. Endogenous human lysosomal alpha-mannosidase is encoded by the MAN2B1 gene.

2.3 Structural Properties of the Jack Bean Enzyme

The enzyme from Canavalia ensiformis is composed of two pairs of subunits (molecular mass 44 and 66 kDa) which form a tetramer (220 kDa). The larger subunit is glycosylated, the smaller one is not. Both subunits have similar amino-acid compositions. Isolation and sequencing of glycopeptides strongly suggests that one high-mannose-type and one complex-type glycan are linked to specific glycosylation sites of the large α-mannosidase subunit. The high-mannose-type glycan, which is a good substrate of the endoglycosidase endo-H, can only be removed from the enzyme after denaturation and cleavage of disulfide bonds by a reducing agent, suggesting that this glycan is buried within the folded polypeptide and thus protected from its hydrolytic activity.

The jack bean enzyme has a broad substrate specificity, cleaving α(1-2, 3, and 6)-linked mannose residues from oligosaccharides and glycoproteins. The enzyme is subject to product inhibition by mannose.

3. Traditional and Historical Use

Alpha-mannosidase as an isolated enzyme does not have a documented history of traditional use in herbal or ethnobotanical medicine as a named preparation. The enzyme itself was first characterised from jack bean and other biological sources in the mid-twentieth century through biochemical research, and its relevance emerged from the study of glycoprotein metabolism and inherited metabolic disease rather than from traditional therapeutic practices.

However, the significance of alpha-mannosidase to human health was underscored when alpha-mannosidosis, as a consequence of decreased activity of alpha-D-mannosidase, was first described in 1967, resembling Hurler syndrome (MIM number 607014). Subsequent decades of biochemical investigation established the enzyme's role in degrading asparagine-linked (N-linked) oligosaccharides, informing modern therapeutic strategies.

The jack bean (Canavalia ensiformis), the richest plant source of alpha-mannosidase, has traditional dietary uses in tropical regions as a legume food source, though the alpha-mannosidase enzyme content of jack beans was not specifically exploited medicinally. The enzyme has been used as a laboratory reagent in glycobiology since the latter half of the twentieth century, providing an exogenous source for structural analysis of glycoproteins and glycans.

The discovery of swainsonine — a potent natural inhibitor of alpha-mannosidase derived from locoweed plants — contributed indirectly to the historical understanding of the enzyme's importance. Legumes belonging to the Astragalus, Oxytropis, and Swainsona genera have been noted by ranchers in the Americas, Asia, and Australia to cause a neurologic disease often referred to as locoism or peastruck. The toxic mechanism was eventually traced to alpha-mannosidase inhibition, informing the understanding of both the enzyme's physiological importance and the consequences of its deficit.

4. Key Constituents and Active Compounds

4.1 The Human Lysosomal Enzyme (MAN2B1)

The MAN2B1 gene provides instructions for making the enzyme alpha-mannosidase, which works in the lysosomes — compartments that digest and recycle materials in the cell. Within lysosomes, the enzyme helps break down complexes of sugar molecules (oligosaccharides) attached to certain proteins (glycoproteins); in particular, alpha-mannosidase helps break down oligosaccharides containing a sugar molecule called mannose.

The MAN2B1 (MANB) gene spans approximately 21.5 kb of DNA and comprises 24 exons. The translational product of this gene consists of 1011 amino acids.

4.2 Class I (GH47) Alpha-Mannosidases

In eukaryotes, class I α-mannosidases are involved in early N-glycan processing reactions and in N-glycan–dependent quality control in the endoplasmic reticulum (ER). In mammals, mannose trimming reactions are catalyzed by class I α-mannosidases (glycosyl hydrolase family 47). These enzymes are inverting glycosyl hydrolases that are highly specific for α1,2-mannose residues and require Ca²⁺ for catalytic activity.

4.3 Golgi Alpha-Mannosidase II (Class II / GH38)

Alpha-mannosidase II (EC 3.2.1.114) is a Golgi enzyme that catalyzes the final hydrolytic step in the asparagine-linked oligosaccharide (N-glycan) maturation pathway, acting as the committed step in the conversion of high mannose to complex type structures. This enzyme has the unusual ability to cleave two different glycosidic linkages in its catalytic center; it removes two terminal mannoses following the activity of N-acetylglucosaminyl transferase I, and is a critical step in the formation of mature glycans.

4.4 Swainsonine: A Key Natural Inhibitor of Alpha-Mannosidase

Swainsonine (C₈H₁₅NO₃) is a naturally occurring indolizidine alkaloid that functions as a potent and reversible inhibitor of α-mannosidases, enzymes involved in glycoprotein processing, particularly in the endoplasmic reticulum and Golgi apparatus. First isolated in 1979 from the Australian plant Swainsona canescens, it is produced by certain plants in the Fabaceae, Convolvulaceae, and Malvaceae families, as well as by endophytic fungi such as Rhizoctonia leguminicola.

Swainsonine inhibits lysosomal α-mannosidase and mannosidase II, resulting in altered oligosaccharide degradation and incomplete glycoprotein processing. It is a potent inhibitor of Golgi alpha-mannosidase II, an immunomodulator, and a potential chemotherapy drug.

5. Mechanisms of Action

5.1 N-Glycan Processing Pathway

The maturation of N-glycans is initiated within the lumen of the endoplasmic reticulum immediately after transfer of the oligosaccharide precursor to nascent polypeptide chains. These glycan processing steps include the sequential cleavage of three glucose (Glc) residues and four α1,2-mannose (α1,2-Man) residues prior to the addition of a GlcNAc residue and cleavage of the final α1,3-Man and α1,6-Man residues. The resulting GlcNAcMan3GlcNAc2-Asn core structure is then extended in the Golgi complex into complex type oligosaccharides.

The endoplasmic reticulum (ER) α1,2-mannosidase I (ERManI) subfamily acts to cleave a single residue from Asn-linked glycans in the ER. The Golgi α-mannosidase I (GolgiManI) subfamily has at least three members in mammalian systems involved in glycan maturation in the Golgi complex to form the Man5GlcNAc2 processing intermediate.

Removal of α1,2-linked mannose residues begins in the endoplasmic reticulum, where trimming of mannose residues has been implicated in the targeting of malfolded glycoproteins for degradation. Removal of mannose residues continues in the Golgi with the action of α1,2-mannosidases IA and IB that can form Man5GlcNAc2, and of α-mannosidase II that removes the α1,3- and α1,6-linked mannose from GlcNAcMan5GlcNAc2 to form GlcNAcMan3GlcNAc2.

5.2 Lysosomal Catabolism of Glycoproteins

Alpha-mannosidase (MAN2B1, EC 3.2.1.24) is a lysosomal enzyme responsible for the degradation of N-linked oligosaccharides. It is necessary for the catabolism of N-linked carbohydrates released during glycoprotein turnover and cleaves all known types of alpha-mannosidic linkages.

5.3 Quality Control and Protein Degradation

The ER/cytosolic mannosidase is proposed to be involved in the degradation of dolichol intermediates that are not needed for protein glycosylation, whereas the soluble form of Man9-mannosidase is responsible for the degradation of glycans on defective or malfolded proteins that are specifically retained and broken down in the ER.

The oligosaccharide processing in the cytosol by PNGase, endo-β-N-acetylglucosaminidase, and alpha-mannosidase may represent the common 'non-lysosomal' catabolic pathway for N-glycans in animal cells, although the molecular mechanism as well as the functional importance of such processes remains to be determined.

5.4 Immunological Effects

The alpha-mannosidase from Canavalia ensiformis has been shown to stimulate the proliferation of B-lymphocytes from nude mice. The oligosaccharide structure on an individual glycoprotein contributes to cell adhesion during development, viral infection, immune response, and metastasis of oncogenically transformed cells.

6. Body Systems and Health Areas

6.1 Lysosomal / Metabolic System

The most direct clinical relevance of alpha-mannosidase to human health relates to its deficiency state. Alpha-mannosidosis is a genetic disorder of metabolism characterised by immune deficiency, facial and skeletal abnormalities, hearing impairment, and intellectual disability. The disorder is caused by lysosomal α-mannosidase deficiency and is inherited in an autosomal recessive fashion.

Alpha-mannosidosis is an ultra-rare monogenic disorder resulting from a deficiency in the lysosomal enzyme alpha-mannosidase, with a prevalence estimated to be as low as 1:1,000,000 live births. The resulting accumulation of mannose-rich oligosaccharides in all tissues leads to a very heterogeneous disorder with a continuum of clinical manifestations with no distinctive phenotypes.

6.2 Nervous System

Alpha-mannosidosis is characterised by impaired intellectual development, coarse facial features, skeletal abnormalities, hearing impairment, neurologic motor problems, and immune deficiency. Clinical manifestations include progressive balance disorders, immune deficiency, skeletal abnormalities, and cognitive deficits beginning in early childhood.

6.3 Immune System

Alpha-mannosidosis presents as a multisystemic disease with features mainly including immune deficiency with recurrent infections early in life, skeletal abnormalities like scoliosis, sternal deformities, hearing impairment, along with gradual impairment in mental and motor functions. Alpha-mannosidase has been shown to inhibit the proliferation of B-lymphocytes in cell-based studies, though the clinical relevance of this observation to supplementation in healthy individuals remains unclear.

6.4 Musculoskeletal System

Clinical features of alpha-mannosidase deficiency include hearing impairment, skeletal and neurological abnormalities, and intellectual disability. Alpha-mannosidosis is a very heterogeneous disorder regarding both disease severity and progression. Patients are able to perform lung function tests and the 6-minute walk test and stair-climb test; these clinical parameters can be used as clinical endpoints for clinical trials. Oligosaccharide levels appear correlated with functional testing and may serve as biomarkers of disease severity, progression, and response to treatment.

6.5 Glycoprotein Processing and Cell Signaling

Because alpha-mannosidase is central to N-glycan processing in the ER and Golgi, its activity is intrinsically linked to the correct folding, trafficking, and function of all N-glycosylated proteins, which include many cell surface receptors, growth factors, and adhesion molecules. Maturation of N-glycans from oligomannose to complex-type structures on cellular and secreted proteins is essential for the roles that these structures play in cell adhesion and recognition events in metazoan organisms.

7. Scientific Evidence by Area of Use

7.1 Enzyme Replacement Therapy for Alpha-Mannosidosis (Velmanase Alfa)

Background: Velmanase alfa is the first human recombinant form of alpha-mannosidase licensed and available for long-term enzyme replacement therapy; it is approved for treating non-neurologic manifestations of mild to moderate alpha-mannosidosis.

Phase III Randomised Controlled Trial: A phase III, double-blind, randomised, placebo-controlled trial was designed to assess the efficacy and safety of velmanase alfa (VA) in alpha-mannosidosis patients. Twenty-five patients were randomised to weekly 1 mg/kg VA or placebo for 52 weeks. Mean relative change in serum oligosaccharide in the velmanase alfa arm was −77.6% (95% CI −81.6 to −72.8) at week 52.

Global Treatment Response Model: After 12 months of treatment, a global treatment response was achieved by 87% of patients receiving velmanase alfa (n = 15) compared with 30% of patients receiving placebo (n = 10).

Phase I/II Trials and Long-Term Data: In phase I/II trials, velmanase alfa was associated with a sustained decrease in serum oligosaccharides after 18 months of therapy (mean percentage change −89.9%, P < 0.001) and achievement of an average improvement of 39 steps in the 3-minute stair climb test (3MSCT; P = 0.004).

Patient data (n = 33; 14 adults, 19 paediatric) from the clinical development programme for velmanase alfa were integrated in a prospectively-designed long-term analysis. Mean treatment exposure was 29.3 (SD 15.2) months. Serum oligosaccharide levels were significantly reduced in the overall population at 12 months.

12-Year Extended Follow-Up: ERT using velmanase alfa previously showed promising efficacy and safety outcomes for up to 4 years of therapy. A pooled analysis from two multicentre, open-label phase IIIb extension trials (rhLAMAN-07, N = 13; rhLAMAN-09, N = 8) evaluated long-term effects. Sixteen patients who previously completed earlier trials and five ERT-naïve patients were enrolled; patients received 1 mg/kg velmanase alfa once weekly. Velmanase alfa treatment was generally well tolerated, with the majority of reported adverse events being of mild-to-moderate intensity, and long-term efficacy and safety outcomes with follow-up of up to 12 years indicate continued benefits.

Motor Proficiency: Long-term integrated analysis of clinical trial safety and efficacy data have shown that improvements in biochemical and functional measures were sustained for up to 4 years, with better functional improvements related to initiation of treatment at an early age. Post-hoc analysis using a global treatment response endpoint incorporating pharmacodynamic, functional, and quality of life measures showed that 87% of individuals receiving velmanase alfa were treatment responders compared to 30% receiving placebo.

Limitations of evidence: The total patient population studied across all velmanase alfa trials is small, as is inherent in the study of an ultra-rare disease. The phase III RCT enrolled only 25 patients; long-term extension studies enrolled between 8 and 21 patients per study. The disease's rarity, phenotypic heterogeneity, and the absence of validated biomarkers for neurological outcomes limit generalisability. Long-term ERT with velmanase alfa is approved in Europe for the treatment of non-neurological manifestations in patients with mild to moderate alpha-mannosidosis. The clinical heterogeneity and rarity of the disease limit the sensitivity of single parameters to detect clinically relevant treatment effects.

7.2 Hematopoietic Stem Cell Transplantation (HSCT)

The primary indication to offer hematopoietic stem cell transplantation in patients affected by alpha-mannosidosis is preservation of neurocognitive function and prevention of early death. HSCT is an effective therapy for selected inherited metabolic diseases with associated neuronal dysfunction, such as Hurler syndrome and cerebral X-linked adrenoleukodystrophy. Unfortunately, effectiveness of ERT is limited owing to its inability to cross the blood-brain barrier (BBB). Thus, bone marrow and hematopoietic stem cell transplantations are the primary options for several lysosomal storage disorders, including severe alpha-mannosidosis.

In a feline model of alpha-mannosidosis, bone marrow transplantation (BMT)-treated animals showed little or no progression of neurologic signs 1 to 2 years after transplant, whereas untreated cats became severely impaired and reached end-stage disease by 6 months of age. Increased lysosomal alpha-mannosidase activity was found in brain tissue of the treated animals, and electron microscopy demonstrated no evidence of lysosomal storage within most neurons.

7.3 Alpha-Mannosidase as a Research Reagent in Glycobiology

In biomedical research, purified jack bean alpha-mannosidase is widely used to release and analyse N-linked glycans from glycoproteins. Alpha-mannosidase liberates mannose from a variety of synthetic and natural α-mannosides and can be used to liberate mannose from a variety of synthetic and natural α-mannosides. It has also been used in a study to investigate the causes of neurodegeneration in mucolipidosis II knock-in mice. This use, while scientifically productive, is entirely a laboratory/research application and has no established relationship to human supplementation.

7.4 Swainsonine and Alpha-Mannosidase Inhibition: Experimental Cancer Research

The inhibition of Golgi alpha-mannosidase II by swainsonine — a naturally occurring plant alkaloid — has been explored in experimental oncology. Swainsonine is a potent inhibitor of Golgi alpha-mannosidase II, an immunomodulator, and a potential chemotherapy drug. Complex-type branched oligosaccharides have been associated with an increase in malignant transformation and cancer metastasis. By virtue of its inhibition of Golgi α-mannosidase II, swainsonine has been under investigation as an antimetastatic agent.

Evidence characterisation: Research on swainsonine as an alpha-mannosidase inhibitor with potential antitumour properties remains largely preclinical (animal models and in vitro). No approved clinical applications exist, and it is noted that the compound also carries significant toxicological risk at doses that inhibit glycoprotein processing (see Safety section below).

7.5 Exogenous Alpha-Mannosidase as a Dietary Supplement (Digestive Use)

Alpha-mannosidase, when taken orally as a supplement, would function as a digestive enzyme acting on α-mannosidic linkages in ingested glycoproteins. However, there is presently no published human clinical evidence from controlled trials specifically evaluating orally administered alpha-mannosidase as a stand-alone dietary supplement in healthy individuals or in specific digestive conditions. Alpha-mannosidase is not characterised in the manner of well-established digestive enzyme supplements (such as alpha-galactosidase or lactase), and no systematic reviews, regulatory monographs, or government health body statements address its oral supplementation in healthy subjects. This absence of clinical data should be clearly noted: any claims about digestive or systemic benefits of orally supplemented alpha-mannosidase in humans lack clinical substantiation as of the available published literature.

8. Dosage Forms and Dosages Reported in Studies

8.1 Enzyme Replacement Therapy (Intravenous)

The only clinically established dosage of alpha-mannosidase (as velmanase alfa, a recombinant human enzyme) is in the setting of alpha-mannosidosis enzyme replacement therapy. In the phase III RCT, twenty-five patients were randomised to weekly 1 mg/kg velmanase alfa or placebo for 52 weeks, administered by intravenous infusion. In extended long-term trials, patients received 1 mg/kg velmanase alfa once weekly.

8.2 Laboratory/Research Preparations

For laboratory use, one unit of jack bean alpha-mannosidase is defined as the amount that will hydrolyze 1.0 μmole of p-nitrophenyl α-D-mannoside to p-nitrophenol and D-mannose per minute at pH 4.5 at 25°C.

No dosage data have been established or published for oral supplementation of alpha-mannosidase in human subjects, and no clinical trial data on oral alpha-mannosidase supplementation are available in the peer-reviewed literature to cite.

9. Safety Considerations and Interactions

9.1 Safety Profile of Velmanase Alfa (Intravenous ERT)

Velmanase alfa treatment was generally well tolerated, with the majority of reported adverse events being of mild-to-moderate intensity. Additional multiple large-scale trials are needed to evaluate the long-term safety and efficacy of velmanase alfa.

9.2 Limitations of Enzyme Replacement Therapy: Blood-Brain Barrier

The effectiveness of ERT is limited owing to its inability to cross the blood-brain barrier (BBB). This is a significant pharmacological limitation, as the neurological manifestations of alpha-mannosidosis remain undertreated by enzyme infusion alone.

9.3 Risks Associated with HSCT for Alpha-Mannosidosis

Bone marrow transplantation/HSCT is associated with complications, namely: graft-versus-host disease (GVHD) that may have lethal consequences; rejection of the transplant; and prophylactic immunosuppressant usage, which elicits substantial side effects.

9.4 Toxicological Consequences of Alpha-Mannosidase Inhibition (Swainsonine)

As the primary toxin in locoweeds like Astragalus and Oxytropis species, swainsonine causes locoism in grazing animals, leading to symptoms including intention tremors, emaciation, reproductive dysfunction, and potentially death through disruption of lysosomal function and glycoprotein metabolism.

Swainsonine inhibits lysosomal alpha-mannosidase and Golgi mannosidase II, ultimately resulting in neuronal swelling and vacuolation due to accumulations of mannose in the lysosomes. Swainsonine toxicosis is an induced storage disease, with clinical signs including ataxia, behavioral changes, and loss of condition.

These animal toxicology data are directly informative about the physiological consequences of alpha-mannosidase inhibition in vivo. They mirror the biochemical pathology observed in hereditary alpha-mannosidosis and confirm the critical importance of intact alpha-mannosidase function.

9.5 Genotype–Phenotype Relationships and Variant Pathogenicity

So far, 155 variants from 191 patients have been identified and in part characterised at the biochemical level. Similarly to other lysosomal storage diseases, there is no relationship between genotype and phenotype in alpha-mannosidosis. More than 120 mutations in the MAN2B1 gene have been identified in people with alpha-mannosidosis.

The disease shows a wide range of clinical phenotypes, from a severe, infantile form (Type I), which is fatal at <3–8 years of age, to a less severe, late-onset form (Type II) involving hearing loss, coarse face, intellectual disability, and mild hepatosplenomegaly, with varying degree of severity.

9.6 Diagnostic Considerations

Elevated urinary secretion of mannose-rich oligosaccharides is suggestive, but not diagnostic, for alpha-mannosidosis. Diagnosis is made by measuring acid alpha-mannosidase activity in leukocytes or other nucleated cells, such as fibroblasts.

9.7 Oral Supplementation: Absence of Safety Data

No published safety data from human clinical trials are available for orally administered alpha-mannosidase as a dietary supplement. The enzyme is a protein and, when ingested, would be subject to proteolytic degradation in the stomach and small intestine, as are other orally administered enzyme supplements. The degree to which intact enzymatic activity would persist in the gastrointestinal lumen is unknown and has not been formally evaluated in published clinical trials. No regulatory body (FDA, EMA, EFSA, WHO) has issued specific guidance or a safety opinion on oral alpha-mannosidase supplementation.

10. Summary of Evidence Quality

Alpha-mannosidase deficiency (alpha-mannosidosis): Well-characterised at the biochemical, genetic, and clinical level. Evidence from multiple phase I/II and a phase III RCT supports the efficacy of recombinant human alpha-mannosidase (velmanase alfa) in reducing serum oligosaccharides and improving functional outcomes in patients with alpha-mannosidosis. Evidence quality: moderate (limited by small sample sizes inherent to an ultra-rare disease).
HSCT for severe alpha-mannosidosis: Supported by animal models and clinical case series; evidence quality low to moderate given lack of RCT data.
Swainsonine/Golgi alpha-mannosidase II inhibition as antimetastatic agent: Preclinical only; no approved human therapeutic use.
Oral alpha-mannosidase supplementation in healthy individuals: No clinical evidence; not addressed by regulatory bodies or evidence-based monographs.
Laboratory/glycobiology uses of jack bean alpha-mannosidase: Well-established research application, not applicable to human health supplementation.

References

Health Conditions

Health conditions that Alpha-mannosidase may help support.

No conditions available.

Body Systems

Body systems that Alpha-mannosidase may help support.

No body systems available.