Purification and characterization of beta-N-acetylhexosaminidase I from human placenta.
beta-N-Acetylhexosaminidase (hexosaminidase) I, which has an intermediate charge character between those of hexosaminidases A(alpha beta 2) and B[beta beta)2), was purified 1,500-fold from human placenta by procedures including chromatographies on concanavalin A (Con A)-Sepharose and an immunoadsorbent column. The isolated hexosaminidase I was heat-stable, and antigenically cross-reactive to anti-beta chain-IgG but not to anti-alpha chain-IgG. The results of substrate specificity experiments using 3H-labeled natural substrates indicated that the hexosaminidase I hydrolyzed Gb4Cer to Gb3Cer but not GM2 to GM3. The tryptic peptide map of the hexosaminidase I was similar to that of hexosaminidase B, though some differences were observed. The hexosaminidase I after treatment with neuraminidase or endo-beta-N-acetylglucosaminidase H was partly converted to less acidic forms. Treatment of the hexosaminidase I with acid phosphatase did not change the charge character. Therefore hexosaminidase I is an acidic variant form of hexosaminidase B, possibly resulting from sialylation and the presence of phosphodiester bonds at the carbohydrate moiety.
Kinoshita
K
K
Biochemistry Laboratory, Hokkaido University School of Medicine.
Taniguchi
N
N
Makita
A
A
Narita
M
M
Oikawa
K
K
D003429:Cross Reactions; D004795:Enzyme Stability; D005260:Female; D054819:Hexosaminidase B; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000276:immunology / Q000302:isolation & purification*; D010449:Peptide Mapping; D010920:Placenta / Q000201:enzymology; D011247:Pregnancy; D013379:Substrate Specificity; D001619:beta-N-Acetylhexosaminidases / Q000276:immunology / Q000302:isolation & purification*
D007527:Isoenzymes; D054819:Hexosaminidase B; D001619:beta-N-Acetylhexosaminidases