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Histidine ball and stick model spinning. Histidine (symbol His or H) [2] is an essential amino acid that is used in the biosynthesis of proteins.It contains an α-amino group (which is in the protonated –NH 3 + form under biological conditions), a carboxylic acid group (which is in the deprotonated –COO − form under biological conditions), and an imidazole side chain (which is partially ...
A polyhistidine-tag, best known by the trademarked name His-tag, is an amino acid motif in proteins that typically consists of at least six histidine (His) residues, often at the N- or C-terminus of the protein. It is also known as a hexa histidine-tag, 6xHis-tag, or His6 tag.
This leader sequence is important for the regulation of histidine in E. coli. The His operon operates under a system of coordinated regulation where all the gene products will be repressed or depressed equally. The main factor in the repression or derepression of histidine synthesis is the concentration of histidine charged tRNAs.
Although histamine is small compared to other biological molecules (containing only 17 atoms), it plays an important role in the body. It is known to be involved in 23 different physiological functions. Histamine is known to be involved in many physiological functions because of its chemical properties that allow it to be versatile in binding.
The three major histatins are 1, 3, and 5, which contains 38, 32, and 24 amino acids, respectively. Histatin 2 is a degradation product of histatin 1, and all other histatins are degradation products of Histatin 3 through the process of post-translational proteolysis of the HTN3 gene product. [9] Therefore there are only two genes, HTN1 and HTN3.
Biosynthesis, i.e., chemical synthesis occurring in biological contexts, is a term most often referring to multi-step, enzyme-catalyzed processes where chemical substances absorbed as nutrients (or previously converted through biosynthesis) serve as enzyme substrates, with conversion by the living organism either into simpler or more complex ...
The endothelial protease vasohibin [f] uses a cysteine as the nucleophile, but a serine to coordinate the histidine base. [43] [44] Despite the serine being a poor acid, it is still effective in orienting the histidine in the catalytic triad. [43] Some homologues alternatively have a threonine instead of serine at the acid location. [43]
Carnosine (beta-alanyl-L-histidine) is a dipeptide molecule, made up of the amino acids beta-alanine and histidine. It is highly concentrated in muscle and brain tissues. [citation needed] Carnosine was discovered by Russian chemist Vladimir Gulevich. [1] Carnosine is naturally produced by the body in the liver [2] from beta-alanine and histidine.