Glyceraldehyde-3-phosphate dehydrogenase release from erythrocytes during haemolysis. No evidence for substantial binding of the enzyme to the membrane in the intact cell

Abstract

Glyceraldehyde-3-phosphate dehydrogenase (G3PDH, EC 1.2.1.12) release from hemolyzing [human] erythrocytes, and its redistribution between free and membrane-bound states were studied with a new type of rapid-mixing filtration apparatus. The apparatus is described. The rate of G3PDH appearance in filtrates is determined not only by the enzyme redistribution but also by the kinetics of hemolysis. The extent of hemolysis was quantified as a function of time, by measuring the amounts of filterable K+ and lactate dehydrogenase. These are cytoplasmic components that are not membrane-bound. When corrected for incomplete hemolysis, extrapolation to zero time indicates that very little G3PDH is membrane-bound in the intact cell.