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STUDY OF THE α‐N‐ACETYLGALACTOSAMINYLTRANSFERASE IN SERA AND RED CELL MEMBRANES OF HUMAN A SUBGROUPS
Author(s) -
Cartron J. P.,
Badet J.,
Mulet C.,
Salmon Ch.
Publication year - 1978
Publication title -
international journal of immunogenetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.41
H-Index - 47
eISSN - 1744-313X
pISSN - 1744-3121
DOI - 10.1111/j.1744-313x.1978.tb00635.x
Subject(s) - enzyme , enzyme assay , allele , red blood cell , biochemistry , biology , gene , erythrocyte membrane , microbiology and biotechnology , membrane , chemistry
SUMMARY The product of the A blood group gene in the erythrocyte membrane and serum from ‘weak A’ variants was investigated using low and high molecular weight acceptors and compared with common A 1 and A 2 blood samples. A reduced enzyme activity was detected, but only in some of the A variants, namely the A 3 (eight out of eleven), A m or A y samples. Other sera from A 3 (three out of eleven), A x , A end or A el individuals were apparently devoid of enzyme activity. A kinetic study by temperature inactivation of A blood group sera also showed that A enzymes are more labile than B enzymes from B I or B II sera. Moreover, in one case (A 3 sample Del.), a very fast inactivation of the A enzyme was observed, suggesting the occurrence of a variant enzyme qualitatively different from the others so far studied. The erythrocyte membrane preparations from all A variants contained no detectable A enzyme activity except for the A 1 and A 2 samples, the former being three to five times more active than the latter. The B enzyme activities from four samples of B RBC tested were comparatively stronger than the A enzyme activity of A 1 RBC. The results were discussed and it was suggested that the synthesis and/or the secretion of the A enzyme in the organism is not uniform from one tissue to another, but could depend on which of the ‘weak A’ alleles or modifier genes is involved.