Hexose-specific inhibition in vitro of human red cell Ca(2+)-ATPase activity.
In a concentration-dependent manner (5.5-27.5 mmol/l), D-glucose incubated in vitro with human erythrocyte membranes at 37 degrees C for 1 h inhibited membrane Ca(2+)-ATPase activity by up to 75%. The IC50 was 11 mmol/l. L-Glucose was ineffective, as were 3-O-methylglucose, 2-deoxyglucose, sorbitol and myo-inositol. In contrast, D-fructose decreased Ca(2+)-ATPase activity nearly as effectively as D-glucose and mannose and galactose at 11 mmol/l were less than 50% as effective as D-glucose. Tunicamycin (12 pmol/l), but not 10 mmol/l aminoguanidine, progressively antagonized in vitro the D-glucose effect on the enzyme. Erythrocyte membrane Ca(2+)-ATPase activity may be regulated by glycosylation, rather than nonenzymatic glycation.
Deziel
M R
MR
Department of Medicine, Albany Medical College, NY 12208.
Safeer
R S
RS
Blas
S D
SD
Davis
F B
FB
Davis
P J
PJ
D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000097:blood*; D004910:Erythrocyte Membrane / Q000201:enzymology*; D006146:Guanidines / Q000494:pharmacology; D006601:Hexoses / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D013329:Structure-Activity Relationship; D014415:Tunicamycin / Q000494:pharmacology
D006146:Guanidines; D006601:Hexoses; D014415:Tunicamycin; D000252:Calcium-Transporting ATPases; C004479:pimagedine