title: Presence of an atypical thermolabile species of beta-hexosaminidase B in metastatic-tumour tissue of human liver.
abstract: An atypical thermolabile species of Hex B (hexosaminidase B) has been found in metastatic-tumour sites of human liver which has a thermostability curve similar to that of Hex A (hexosaminidase A), which is present in decreased amounts relative to the Hex A isoenzyme, and which exhibits decreased relative activity at acidic pH values (2.6-3.6) when compared with control-liver Hex B. This atypical Hex B isoenzyme has a normal apparent Michaelis constant (0.6 mM) for 4-methylumbelliferyl 2-deoxy-2-acetamido-beta-D-glucopyranoside. The presence of this atypical Hex B suggests that variant beta-chains are being produced in metastatic-tumour tissue.
mesh_terms: D000118:Acetylglucosaminidase / Q000378:metabolism; D054818:Hexosaminidase A; D054819:Hexosaminidase B; D006596:Hexosaminidases / Q000378:metabolism*; D006358:Hot Temperature; D006801:Humans; D007525:Isoelectric Focusing; D007527:Isoenzymes / Q000378:metabolism; D007700:Kinetics; D008113:Liver Neoplasms / Q000201:enzymology* / Q000556:secondary; D012709:Serum Albumin / Q000494:pharmacology; D001619:beta-N-Acetylhexosaminidases
chemical_list: D007527:Isoenzymes; D012709:Serum Albumin; D006596:Hexosaminidases; D000118:Acetylglucosaminidase; D054818:Hexosaminidase A; D054819:Hexosaminidase B; D001619:beta-N-Acetylhexosaminidases