Open Accessl ‐Phenylalanine: tRNA Ligase of Escherichia coli K10
Author(s) -
PIMMER Jutta,
HOLLER Eggehard,
ECKSTEIN Fritz
Publication year - 1976
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1976.tb10646.x
Subject(s) - chemistry , ternary complex , nucleotide , adenosine triphosphate , stereochemistry , enzyme , thio , escherichia coli , phenylalanine , dna ligase , transfer rna , phosphate , biochemistry , amino acid , rna , gene
The K m and V values of the tRNA‐charging reaction have been measured for l ‐phenylalanine: tRNA ligase and the geometric isomers of adenosine 5′‐O‐(1‐thio)triphosphate, adenosine 5′‐O‐(2‐thio)triphosphate and for 5′‐O‐(3‐thio)triphosphate. All ATP analogs were found to be substrates with values of K m similar or (up to 10‐fold) higher, and with values of V in the range of 10–30% compared with the natural substrate. The dissociation constants of the binary enzyme · nucleotide and ternary enzyme · nucleotide · l ‐phenylalaninol complexes were analysed as a function of the position of the sulfur atom indicating those phosphate groups which are involved in an enzyme‐triphosphate interaction. The results are consistent with a participation of the β and γ‐phosphate in the binary complex formation and an additional interaction at the positions of the α and β‐phosphate groups in the ternary complexes.