Involvement of conserved asparagine and arginine residues from the N-terminal region in the catalytic mechanism of rat liver and Trypanosoma cruzi tyrosine aminotransferases.

ABSTRACT: Rat liver and Trypanosoma cruzi tyrosine aminotransferases (TATs) share over 40% sequence identity, but differ in their substrate specificities. To explore the molecular features related to these differences, comparative mutagenesis studies were conducted on full length T. cruzi TAT and N-terminally truncated rat TAT recombinant enzymes. The functionality of Arg315 and Arg417 in rat TAT was investigated for comparison with the conserved Arg292 and Arg386 in aspartate and bacterial aromatic aminotransferases (ASATs and ARATs). The rat TAT Arg315Lys variant remained fully active indicating that, as in T. cruzi TAT and contrary to subfamily Ialpha aminotransferases, this residue is not critical for activity. In contrast, the Arg417Gln variant was inactive. The catalytic relevance of the putat

SUBMITTER: Sobrado VR 

PROVIDER: S-EPMC2323874 | biostudies-literature | 2003 May

REPOSITORIES: biostudies-literature