Evolutionary convergence in the biosyntheses of the imidazole …
2018年4月26日 · The imidazole group is an ubiquitous chemical motif present in several key types of biomolecules. It is a structural moiety of purines, and plays a central role in biological catalysis as part of the side-chain of histidine, the amino acid …
Histidine - Wikipedia
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 protonated), classifying it as a positively charged amino acid at physiological pH.
Biochemistry, Histidine - StatPearls - NCBI Bookshelf
2023年7月30日 · Histidine’s imidazole side chain is unique amongst amino acids, giving rise to its aromaticity and amphoteric properties at physiologic pH. This property makes histidine a key catalytic residue in many enzymes. Histidine also performs important anti-inflammatory, anti-oxidant, and anti-secretory functions within the body.
Histidine Biosynthesis - PMC
Histidine (His) is one of the standard amino acids in proteins, and plays a critical role in plant growth and development. The chemical properties of the imidazole side group allow His to participate in acid-base catalysis, and in the co-ordination ...
Imidazole - Wikipedia
Imidazole is incorporated into many important biological compounds. The most pervasive is the amino acid histidine, which has an imidazole side-chain. Histidine is present in many proteins and enzymes, e.g. by binding metal cofactors, as seen in hemoglobin. Imidazole-based histidine compounds play a very important role in intracellular ...
The multiple roles of histidine in protein interactions
2013年3月1日 · The side chain imidazole of histidine is an aromatic motif; an ionizable group with the acidic ionization constant around pK a =6.5; a coordinating ligand of metallic cations (for example, Ca 2+ and Zn 2+); and a hydrogen bond donor and acceptor. The unique structure of histidine makes it plays multiple roles in the molecular interactions.
Alkaloids Derived from Histidine: Imidazole (Pilocarpine, Pilosine ...
2013年1月1日 · This chapter will cover the alkaloids containing the imidazole nucleus which is the smallest group of alkaloids in terms of number of compounds known. This class of alkaloids is synthesized by precursors derived directly from the amino acid, l-histidine.
Revisiting the pH-gated conformational switch on the ... - Nature
2020年2月7日 · Histidine is a versatile residue playing key roles in enzyme catalysis thanks to the chemistry of its imidazole group that can serve as nucleophile, general acid or base depending on its...
Chapter 9 Imidazoles - ScienceDirect
2007年1月1日 · The imidazole ring is present in a number of biologically important molecules as exemplified by the amino acid histidine. It can serve as a general base or a ligand for various metals (e.g. Zn, etc.) in biological systems.
important imidazole molecules are shown: histidine (2-amino-3-(1H-imidazol-4-yl), adenine (9H–purin-6-amine), adenosine monophosphate (N9-ribosyl-adenine), and N6-ribosyladenine (which synthesis has been reported in prebiotic chemistry experiments).