Search results
Results From The WOW.Com Content Network
[5] [6] [7] The imidazole/imidazolium ring of histidine is aromatic at all pH values. [8] Under certain conditions, all three ion-forming groups of histidine can be charged forming the histidinium cation. [9] The acid-base properties of the imidazole side chain are relevant to the catalytic mechanism of many enzymes. [10]
Arginine has a charged guanidino group and lysine a charged alkyl amino group, and are fully protonated at pH 7. Histidine's imidazole group has a pK a of 6.0, and is only around 10% protonated at neutral pH. Because histidine is easily found in its basic and conjugate acid forms it often participates in catalytic proton transfers in enzyme ...
Chemical formula: C 6 H 9 N 3 O 2 Molar mass: 155.16 g·mol −1 Systematic name: 2-amino-3-(3H-imidazol-4-yl)propanoic acid Abbreviations: H, His Synonyms: Imidazole alanine ({S/D})-α-amino-1H-imidazole-4-propanoic acid
When the acidic proton is replaced by alkyl, the compounds are called N-alkylpyridinium. A simple representative is N -methylpyridinium ( [C 5 H 5 NCH 3 ] + ). These pyridinium intermediates have been used as electrophiles in synthetic organic chemistry to build dearomatized congeners called dihydropyridines, as demonstrated in one example from ...
The compound added at high concentration replaces virtually all carrier-bound protein which is thus eluted from the carrier. Imidazole is the side chain of histidine and is typically used at a concentration of 150 - 500 mM for elution. Histidine or histamine can also be used. Decrease in pH
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]
The isoelectric point (pI, pH(I), IEP), is the pH at which a molecule carries no net electrical charge or is electrically neutral in the statistical mean. The standard nomenclature to represent the isoelectric point is pH(I). [ 1 ]
3 3D structure. 5 comments. 4 Aromaticity. 12 comments. ... 1 comment. 6 Synthesis and precursors. 3 comments. 7 pKa. 1 comment. 8 Molecular Formula. 3 comments. 9 23 ...