The essentiality of histidine in healthy adults is a controversial topic. To study the potential metabolic effects of a lack of exogenous histidine, four healthy adults consumed a histidine-free diet, with adequate energy and 1.0 g/(kg d) of an L-amino acid mixture for 48 d. Protein metabolism was monitored every 4 d by using indicator amino acid (L-[1-C]phenylalanine) oxidation (in four subjec...

The essentiality of histidine in healthy adults is a controversial topic. To study the potential metabolic effects of a lack of exogenous histidine, four healthy adults consumed a histidine-free diet, with adequate energy and 1.0 g/(kg. d) of an L-amino acid mixture for 48 d. Protein metabolism was monitored every 4 d by using indicator amino acid (L-[1-(13)C]phenylalanine) oxidation (in four s...

Anabaena apoflavodoxin contains a single histidine residue (H34) that interacts with two aromatic residues (F7 and Y47). The histidine and phenylalanine rings are almost coplanar and they can establish a cation-pi interaction when the histidine is protonated. The histidine and tyrosine side-chains are engaged in a hydrogen bond, which is their only contact. We analyse the energetics of these in...

Peptides have shown Promising effect as pharmaceutics with the potential to treat a widevariety of diseases. Peptides are mostly synthesized by biological technology or chemicalmethods. Solution phasepeptide synthesis (SPS) and solid phase peptide synthesis (SPPS) aretwo major chemical techniques for peptidesproduction.In this research, the synthesis ofdipeptde(β-alanine-L-histidine)wasexamined...

In the present work, an extensive theoretical calculation study on Histidine-Histidine dipeptide in gas phase is done by using DFT method with Gaussian 98 program. Through investigations on the molecular geometries of this molecule it is found that there is six rings in the molecules not two rings. The presence of four intramolecular hydrogen bonds is responsible for the formation of additional...

In this paper, the ultrasonic absorption of amino acids was measured using a small cylindrical resonator at physiological pH and 25°C and a concentration of 0.1. M. The absorption of mixtures of some amino acids was also measured. In the case of cysteine-histidine, the absorption of mixtures is much larger (more than twice) than the summation of absorption of the individual amino acid. This...

Introduction.-In several instances, the rate of synthesis of the enzymes of a biosynthetic pathway appears to be regulated by the size of the pool of the end product of that pathway.1-4 This phenomenon has been called enzyme repression.2 We have observed repression by histidine during the investigation of the histidine biosynthetic enzymes in histidine-requiring mutants of Salmonella typhimuriu...

Control of formation of the histidyl-transfer ribonucleic acid (tRNA) synthetase with an increased K(m) for histidine was studied in a hisS mutant of Salmonella typhimurium. Histidine restriction of both the hisS and hisS(+) strains resulted in a derepression of synthesis of histidyl-tRNA synthetase. When grown in a concentration less than the K(m) (100 mug/ml) of l-histidine, the hisS mutant m...

The regulation of the histidine-degrading pathway is known to involve induction and repression. Our studies have shown that succinate may control the histidine-degrading pathway by sequential negative feedback inhibition. Succinate inhibited urocanase, and urocanate in turn inhibited histidase. Crude preparations of the two enzymes were made from Pseudomonas putida grown on l-histidine. Succina...

Histidine is a crucial amino acid for growth in S. cerevisiae and plays other important roles for survival in larger eukaryotes. Histidine auxotrophs, organisms that cannot synthesize histidine, often exhibit inhibited growth and development. Research of the model organism, Saccharomyces cerevisiae, illuminates eukaryotic uses of amino acids in other eukaryotes. Researchers have also begun to u...