Significance of the variation in isozymes of liver lactate dehydrogenase with thermal acclimation in goldfish--I. Thermostability and temperature dependency.

1. Total and isozyme properties as well as isozyme pattern were examined in liver lactate dehydrogenase (LDH) from goldfish acclimated to different temperatures. 2. LDH of warm-acclimated fish were thermostable and exhibited higher Q10 in low temperature range as compared with that of co ld-acclimated fish. 3. The relative activities of LDH-1, LDH-2 and LDH-3, which were more thermostable, increased and LDH-4 and LDH-5, which were more heat sensitive, decreased during warm acclimation. Q10 in the low temperature range for LDH-5 was lower than that for LDH-1.