Studies on denaturation of enzymes - I. Prevention of inactivation of lactate dehydrogenase of carp muscle during extraction, purification and dilution.

Abstract

Lactate dehydrogenase (LDH) of garp muscle is inactivated during extraction and succeeding purification prceses. Inactivation is found also in dilutiion process which is done prior to the activity determintion. When LDH was extracted and purified with media containing sodium glutamate, the obtained LDH samples demonstrated higher activity than those prepared with water media. By using medis containing 0.1M sodium glutamate in place of the water medis of KORNBEG'S purification method, th specific activity of the LDH sample was raised mardidly. Dilution with glutamate containing media also raised the activity. These effects were attriuted to the preventioin of the inativation of LDH. Similar preventive effect was tested on several media. namely eter, 0.15M NaCl, 5mM DTT, 0.25M sucrose, 10% glycerol an d0.1M sodium glutamate. Cros effects of these media were also tested. Glutamate was found most effective, sucrose the next, and glycerol third, while other media were of little effect or none. The resultant LDH samples were as active as over 200 units permg protein. The LDH activity was determined by KUBOWITZ's method.