Effects of some metabolic intermediates on AMP-deaminase activity in denervation atrophy.

Effects in vitro of glutamate, aspartate, fumarate and malate on substrate activation kinetics of AMP-deaminase in denervated and contralateral gastrocnemius muscles of the frog, Rana hexadactyla were studied. Glutamate increase the enzyme activity of both muscles by increasing maximal velocity (V) and decreasing Michaelis-Menten constant (Km), whereas, aspartate did not show any significant effect. Fumarate and malate exerted mixed type of inhibition by decreasing V and increasing Km of enzymes in both muscle preparations. The inhibitor constant (Ki) values suggest that the denervated muscle enzyme was more sensitive to fumarate and malate as compared to the contralateral muscle enzyme.