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...

To investigate the cause of low serum histidine in rheumatoid arthritis (RA) single oral and intravenous doses of L-histidine were administered to patients with active RA, and to an equal number of age and sex matched control subjects. In the first study 13 patients and their controls received a 100 mg kg-1 dose of L-histidine as an aqueous slurry. Significant differences were seen in body weig...

It has previously been shown that the enzymes that catalyze the first two steps, L-histidine ammonia-lyase and urocanase, are induced by L-histidine and repressed by catabolites (4, 5). It will be shown in the present paper that the enzyme catalyzing the fourth step of the sequence, N-formimino-r-glutamate formiminohydrolase, is also subject to induction by n-histidine and repression by catabol...

A histidine fermenting Clostridium was isolated in this laboratory by Dr. Arthur Kornberg by standard enrichment culture techniques. This bacterium, which can use either L-histidine or i-glutamic acid as a primary energy source, has been identified as Clostridium tetanomorphum (Breed et al., 1948). Cell suspensions of the organism have been shown to form carbon dioxide, ammonia, hydrogen, forma...

Mouse embryos recovered on the 4th day of pregnancy produced histamine, as evidenced by the 14CO2 produced from carboxy labelled L-histidine, at the rate of 1.5 +/- 0.3 (s.e.m.) pmol/embryo per hour. Most (83.2 +/- 4.6%) of the embryos flushed from the oviducts on Day 3 of pregnancy (4--8-cell stage) developed into blastocysts within 48 h after being placed in culture. Inclusion of L-histidine ...

Carnosinases are Xaa-His dipeptidases that play diverse functions throughout all kingdoms of life. Human isoforms of carnosinase (CN1 and CN2) under appropriate conditions catalyze the hydrolysis of the dipeptides carnosine (β-alanyl-L-histidine) and homocarnosine (γ-aminobutyryl-L-histidine). Alterations of serum carnosinase (CN1) activity has been associated with several pathological conditio...

Histidine is an amino acid precursor of neuronal histamine. It is evident that peripheral injection of histidine produces effects that resemble to centrally administered histamine. The aim of the present study was to compare the effects of intracerebroventricular (ICV) injection of histamine and inraperitoneal (IP) injection of histidine on food intake in rabbits. ICV injections of histamine (1...

This study evaluates the effects of carbon, nitrogen, and sulfur dopants on photocatalytic activity TiO2 for degradation oxytetracycline (OTC) chemical oxygen demand (COD) removal from licorice extraction plant wastewater (LEPW). Three novel visible-light-responsive nanostructures, including L-Histidine-TiO2, L-Methionine-TiO2 L-Asparagine-TiO2, were successfully synthesized. The results showed...

The single histidine residue (His-15) in hen egg white lysozyme (EC 3.2.1.17) was chemically modified by diethyl pyrocarbonate (DEPC) to form exclusively the mono-N-carbethoxyimidazole adduct (second order rate constant of 252 +/- 16 M-1 min-1). Irreversible biscarbethoxylation of the His-15 imidazole ring by DEPC was observed when lysozyme was pretreated with 2-mercaptoethanol (2-ME), 2-ME plu...