[Hydrolytic activity of bovine tryptophanyl-tRNA-synthetase cause by removal of Zn2+].
Bovine tryptophanyl-tRNA synthetase (E.C.6.1.1.2) lacking Zn2+ ions removed by chelation with phosphonate analog of P1,P4-bis-(5'-adenosyl)tetraphosphate (Ap4A) was obtained (E-Zn). E-Zn lost the ability to form tryptophanyl adenylate, however it hydrolyses ATP to ADP and further on to AMP and Pi. GTP serves as a substrate with Km approximately 0.6 mM. It is proposed that the hydrolysable nucleotides bind to a nucleotide binding site(s) distinguishable from the substrate (catalytic) ones. After incubation of E-Zn with Zn2+ and Mg2+ the initial catalytic activity (ATP-PPi exchange and amino-acylation reactions) is restored whereas the hydrolytic activity becomes fully suppressed.
Kovaleva
G K
GK
Tarusova
N B
NB
Kiselev
L L
LL
D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D000818:Animals; D002384:Catalysis; D002417:Cattle; D015226:Dinucleoside Phosphates; D006868:Hydrolysis; D007700:Kinetics; D010179:Pancreas / Q000201:enzymology; D010710:Phosphates / Q000378:metabolism; D014369:Tryptophan-tRNA Ligase / Q000378:metabolism*; D015032:Zinc
D015226:Dinucleoside Phosphates; D010710:Phosphates; C020733:diadenosine tetraphosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000604:Amino Acyl-tRNA Synthetases; D014369:Tryptophan-tRNA Ligase; D015032:Zinc
Gidroliticheskaia aktivnost' bych'eĭ triptofanil-tRNK-sintetazy, vyzvannaia udaleniem iona Zn2+.