A-N-acetylgalactosaminidase
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A-N-acetylgalactosaminidase
α-N-acetylgalactosaminidase (EC 3.2.1.49) is a glycoside hydrolase from bacteria and animals.
The human gene that codes for this enzyme is NAGA. Mutations in this gene and the deficiency in alpha-N-acetylgalactosaminidase activity have been identified as the cause of Schindler disease.[1]
A-N-acetylgalactosaminidase or Nagalase (EC/3.2.1.49) is a glycoside hydrolase from bacteria and animals and promotes immune suppression by inactivating Macrophages.
Alpha-N-acetyl galactosaminidase (alpha-NaGalase) has been reported to accumulate in serum of cancer patients and be responsible for deglycosylation of Gc protein, which is a precursor of Gc-MAF-mediated macrophage activation cascade, finally leading to immunosuppression in advanced cancer patients.
Alpha-NaGalase
"The biochemical characterization of alpha-NaGalase from several human tumor cell lines were studied. We also examined its effect on the potency of GcMAF to activate mouse peritoneal macrophage to produce superoxide in GcMAF-mediated macrophage activation cascade. The specific activity of alpha-NaGalases from human colon tumor cell line HCT116, human hepatoma cell line HepG2, and normal human liver cells (Chang liver cell line) were evaluated using two types of substrates; GalNAc-alpha-PNP (exo-type substrate) and Gal-beta-GalNAc-alpha-PNP (endo-type substrate).
Tumor-derived alpha-NaGalase having higher activity than normal alpha-NaGalase, had higher substrate specificity to the exo-type substrate than to the endo-type substrate, and still maintained its activity at pH 7. GcMAF enhance superoxide production in mouse macrophage, and pre-treatment of GcMAF with tumor cell lysate reduce the activity.
We conclude that tumor-derived alpha-NaGalase is different in biochemical characterization compared to normal alpha-NaGalase from normal Chang liver cells. In addition, tumor cell-derived alpha-NaGalase decreases the potency of Gc-MAF on macrophage activation."[2]
References
- ^ Wang AM, Schindler D, Desnick R (November 1990). "Schindler disease: the molecular lesion in the alpha-N-acetylgalactosaminidase gene that causes an infantile neuroaxonal dystrophy". J. Clin. Invest. 86 (5): 1752–6. doi:10.1172/JCI114901. PMC 296929. PMID 2243144. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=296929.
- ^ Tumor cell alpha-N-acetylgalactosaminidase activity and its involvement in GcMAF-related macrophage activation / tten by Saharuddin B. Mohamad, Hideko Nagasawa, Yoshihiro Uto and Hitoshi Hori (2001)Elsevier, Volume 132, Issue 1, May 2002, Pages 1–8, Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology
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