Uptake of amino acids is a complex process but in cells growing with ammonia as sole nitrogen source the initial uptake rate of amino acids is a measure of the transport capacity of the uptake system (permease). In synchronous cultures of Saccharomyces cerevisiae amino acids were transported at all stages of the cell cycle. However, for any one amino acid the initial uptake rate was constant fo...

The human phenylalanine hydroxylase gene (PAH) (locus on human chromosome 12q24.1) contains the expressed nucleotide sequence which encodes the hepatic enzyme phenylalanine hydroxylase (PheOH). The PheOH enzyme hydroxylates the essential amino acid l-phenylalanine resulting in another amino acid, tyrosine. This is the major pathway for catabolizing dietary l-phenylalanine and accounts for appro...

Non-ribosomal peptide synthetases (NRPS) are a family of enzymes that assemble a variety of pharmacologically interesting polypeptides from canonical and non-canonical amino acids. The identity and connectivity of the monomers in the final product are directly determined by the order of domains in the enzyme that are specific for the recognition and incorporation of a particular amino acid. Her...

The transamination of aromatic l-amino acids (5-hydroxytryptophan, tryptophan, tyrosine, phenylalanine and kynurenine) was shown to be catalysed by enzyme preparations from rat small intestine. On the basis of the partial purification and characterization of these aromatic amino acid transaminases, it is suggested that rat small intestine contains several kinds of aromatic amino acid transamina...

Genetic breeding of microbial amino acid producers has been done conventionally by acquiring auxotrophic mutants or regulatory mutants based on fundamental knowledge of amino acid biosynthetic pathways and their regulatory mechanisms. The conventional techniques are effective in that a number of amino acids, such as lglutamate, L-lysine, L-phenylalanine, L-threonine, larginine, L-isoleucine, L-...

The metabolism of phenylalanine and tyrosine has been the subject of investigation for many years. Much evidence has been produced to show that in mammalian tissue phenylalanine is converted to tyrosine (l-5). Tyrosine can be oxidized to p-hydroxyphenylpyruvic acid, which can in turn form homogentisic acid (5-13). Embden, Salomon, and Schmidt (14) showed that phenylalanine, tyrosine, and homoge...

The induced uptakes of L-[3H]phenylalanine and L-[3H]arginine in oocytes injected with clonal NBAT (neutral and basic amino acid transporter) cRNA show differential inactivation by pretreatment with N-ethylmaleimide (NEM), revealing at least two distinct transport processes. NEM-resistant arginine transport is inhibited by leucine and phenylalanine but not by alanine or valine; mutual competiti...

The present study reports in silico investigation of bioactive compounds from marine microalgae capable escalating copepod fecundity potential through enhanced heat shock protein (HSP-70) production. structure ligand (bioactive microalgae) and hsp-70 obtained the databases PubChem Protein Data Bank (PDB), respectively. Molecular Docking was performed by GOLD software interaction pathways using ...

Thiobacillus neapolitanus, a strict chemoautotroph, is sensitive to the addition of 10(-4)m methionine, histidine, threonine, or phenylalanine to the thiosulfate medium on which it grows. When histidine, threonine, or phenylalanine are added at the time of inoculation, spontaneous mutants tolerant to the three amino acids are selected. These mutants appear to result from a single genetic change...

Muscle mass declines with aging. Amino acids alone stimulate muscle protein synthesis in the elderly. However, mixed nutritional supplementation failed to improve muscle mass. We hypothesized that the failure of nutritional supplements is due to altered responsiveness of muscle protein anabolism to increased amino acid availability associated with endogenous hyperinsulinemia. We measured muscle...