抄録
The influence of various nucleotides on the activity of AMP deaminase (EC 3. 5. 4. 6) from skeletal muscle of snapper Pagrus auratus has been investigated. The enzyme was activated by 1mM adenine nucleotides such as ATP and ADP. The substrate-saturation curve of the enzyme was sigmoidal in the absence of effectors, but it changed to a hyperbolic curve through the addition of ATP, ADP, and K+. ATP proved to have a biphasic effect on the enzyme, in other words the enzyme was inhibited by ATP at a low concentration of 0.1mM and activated at a higher concentration.
The enzyme activity was inhibited effectively by GTP ranging from 0.1 to 5mM at a substrate concentration of 1mM AMP, and the inhibitory ratio showed a maximum value of 67% by the addition of 0.1mM GTP in the absence of K+, while 50mM KCl can essentially reverse the inhibition of the enzyme activity by GTP.
The regulatory property of snapper muscle AMP deaminase activated by ATP is similar to those of the enzymes from the internal organs of animals, the muscle of other fishes, and baker's yeast.
