Adenosine triphosphate-activated adenylate deaminase from marine invertebrate animals. Properties of the enzyme from lugworm (Arenicola cristata) body-wall muscle.
Adenylate deaminase (AMP aminohydrolase, EC 3.5.4.6) from lugworm (Arenicola cristata) body-wall muscle was partially purified by extraction in KCl solutions and chromatography on phosphocellulose. Enzyme activity was eluted from the column at two salt concentrations. Both forms show co-operative binding of AMP (Hill coefficient, h, 2.85) with s0.5 values of 20 mM and 15.6 mM. ATP and ADP act as positive effectors lowering h to 1.07 and s0.5 to 2mM. The apparent Ka (activation) for ATP was 1.5mM. GTP is an inhibitor with an apparent Ki of 0.12 mM. In vivo the ATP-activated adenylate deaminase is in the active form and may be regulated by changes in GTP concentrations. Adenylate deaminase may act as a primary ammonia-forming enzyme in ammonotelic marine invertebrates with the purine nucleotide cycle.
D000659:AMP Deaminase / Q000302:isolation & purification*; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000818:Animals; D004789:Enzyme Activation; D006863:Hydrogen-Ion Concentration; D009132:Muscles / Q000201:enzymology; D009709:Nucleotide Deaminases / Q000302:isolation & purification*; D011077:Polychaeta / Q000201:enzymology*
D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D009709:Nucleotide Deaminases; D000659:AMP Deaminase