Two lactate dehydrogenases, L(+)- and D(−)- lactate cytochromecreductase, were extracted from the baker's yeast after disintegration of the cells by a FRENCH press. They are separated by electrophoresis on polyacrylamide gel and their activities were compared by color density of formazan, the reduction product of nitroblue tetrazolium.The ratio of L-lactate cytochromecreductase activity to D-lactate cytochromecreductase activity varied to a great extent, depending on culture conditions. L-Lactate cytochromecreductase was predominant in resting cells; the reverse was the case with cells in early exponential stage of the growth.When the cells in exponential stage of growth were aerated without nitrogen source, there occurred an intensive increase of L-lactate cytochromecreductase, accompanied by the decrease of D-lactate cytochromecreductase.Effects of inhibitors on the activity ratio of these two enzymes were investigated.o-Phenanthroline, dinitrophenol, sodium azide, chloramphenicol, British antilewisite and antimycin A favored, in this order, the formation of L-lactate cytochromecreductas
展开▼
