L-Valyl-L-glutamine andL-glutamyl-L-valine

Uptake of L-valyl-L-valine and glycylsarcosine by hamster jejunum in vitro.

The synthesis and the enzymatic degradation of l-tyrosyl-l-lysyl-l-glutamyl-l-tyrosine.

The formation of angiotonin from the serum protein fraction art-globulin and renin (1, 2) as well as its inactivation by proteolytic enzymes suggests that this pressor substance contains peptide linkages. Preliminary studies and interpretations (3) of the action of crystalline proteolytic enzymes led to the conclusion that angiotonin contains groupings of which the simplest representation is af...

Structural Basis for Double-Sieve Discrimination of L-Valine from L-Isoleucine and L-Threonine by the Complex of tRNAVal and Valyl-tRNA Synthetase

Valyl-tRNA synthetase (ValRS) strictly discriminates the cognate L-valine from the larger L-isoleucine and the isosteric L-threonine by the tRNA-dependent "double sieve" mechanism. In this study, we determined the 2.9 A crystal structure of a complex of Thermus thermophilus ValRS, tRNA(Val), and an analog of the Val-adenylate intermediate. The analog is bound in a pocket, where Pro(41) allows a...

A non-planar peptide bond in L-seryl-L-valine.

The molecular structure of (I) is shown in Fig. 1. Bond lengths and angles are normal, but the unusual non-planarity of the peptide bond is quite evident. The associated torsion angle C1ÐC3ÐN2ÐC4 (!) is 157.37 (15) , a deviation from 180 that is superceded among small chiral peptides only by the 156.6 ! angle in N-(tert-butoxycarbonyl)-l-Pro-l-Leu benzyl ester (Sugino et al., 1978). Fig. 2(a) s...

Intestinal renal metabolism of L-citrulline and L-arginine following enteral or parenteral infusion of L-alanyl-L-[2,15N]glutamine or L-[2,15N]glutamine in mice.

Previously, we observed increased plasma arginine (ARG) concentrations after glutamine (GLN)-enriched diets, in combination with clinical benefits. GLN delivers nitrogen for ARG synthesis, and the present study was designed to quantify the interorgan relationship of exogenous L-GLN or GLN dipeptide, by enteral or parenteral route, contributing to intestinal citrulline (CIT) and renal de novo AR...