C. J. EPSTEIN, C. W. SMITH and LILLIAN W. KWOK
H. SPIELMANN, R. P. ERICKSON and C. J. EPSTEIN
Lactate dehydrogenase and glucose-6-phosphate dehydrogenase in Day-1 and Day-4 preimplantation mouse embryos was assayed by immunotitration. For both enzymes, immunoreactive protein was found to decrease in parallel with enzyme activity, indicating that loss of activity is probably the result of enzyme degradation. The identification of embryonic lactate dehydrogenase as isoenzyme LDH-1 and of glucose-6-phosphate dehydrogenase as the form found in red cells is corroborated by the immunological data.