Nucleic Acids Research, 1977, Vol. 4, No. 3 673-683
© 1977
Articles |
On the binding of aminoalkyl adenytates to isoleucyl-tRNA synthetase from Escherichia coli MRE 600
Gesellschaft für Biotechnologische Forschung mbH Mascheroder Weg 1, 3300 Braunschweig-Stockheim, GFR
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Received January 12, 1977. The binding of nine aminoalkyl adenylates to isoleucyl-tRNA synthetase from Escherichia coli MRE 600 was measured and compared with the binding of the cognate amino acids. It was found that they bind.rather tightly to the enzyme, the K ranging from 3.1.104 M with glycinol-AMP ester to 3.7.189 M with L-isoleucinol-AMP ester. The binding is not affected by magnesium. It is shown that the free energies of binding of the esters can be calculated adding a constant contribution of the AMP-moiety of about - 4.1 (- 17) kcal/mole (kJ/mole) to the free energies of binding of the cognate amino acids, which we have reported earlier (19,25,26).