Lactate Dehydrogenase Isozymes: Further Kinetic Studies at High Enzyme Concentration

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Science  31 Jul 1970:
Vol. 169, Issue 3944, pp. 480-481
DOI: 10.1126/science.169.3944.480


By competition with lactate dehydrogenase (LDH) for nicotinamide adenine dinucleotide (NAD), commonly occurring intracellular proteins, such as glyceraldehyde-3-phosphate dehydrogenase, malate dehydrogenase, and albumin, can protect LDH-1 and LDH-5 from inhibition and ternary complex formation with NAD and pyruvate. The existence of intracellular proteins that compete with LDH for NAD renders unphysiological a model for estimating the extent of intracellular LDH inhibition based on incubations of only LDH, NAD, and pyruvate.

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