Prosthetic group protease

Limited proteolysis (Solomonson et al., 1986 Kubo et al., 1988 Notton et al., 1989) and radiation inactivation experiments (Solomonson et al., 1987) have shown that NR is organised in functional domains, as initially suggested by Brown et al. (1981). Each of the prosthetic groups is held in one of three catalytic domains which are linked one to another by protease sensitive hinges. Intersubunit interactions occur via the MoCo domain. After cleavage of either of the two hinges, NADH NR activity is lost but each domain, or pair of domains, retains its specific functional redox properties. This approach has revealed that each of the partial enzymatic activities of NR can be ascribed to one specific domain, or to... 

Promise Prosthetic group/Metal enzymes Proteases... 

Cytochrome Cj contains a c-type haem as prosthetic group in its wedge-shaped N-terminal domain located in the inter-membrane space. This extrinsic domain is anchored to membrane by a transmembrane helix at the C-terminal end (residues 204 to 222 in bovine bc ). This helix runs alongside cytochrome b and can be removed by mild protease treatment or gene truncation to produce a protein fragment (Hase et al., 1987 Li et al., 1981). 

Metal Ions in Coenzymes - Many enzymes contain metal ions, usually held by coordinate covalent bonds from amino acid side chains, but sometimes bound by a prosthetic group like heme. Such enzymes are called metalloenzymes. Figure 11.27 shows the active site of the protease carboxypeptidase A, which contains a zinc ion. 

Propylene, 167. See also Propene Propylene glycol, 589 Propylene oxide, 248. See also 1,2-Epoxypropane Propyl group, 65 Propyl radical, 151—152 Prostacychns, 1045 Prostaglandins, 736, 1024—1025 Prosthetic groups. See Coenzymes Protease inhibitors, 1099 Protecting groups acetals as, 671—672 for amino acids, 1077—1079 for arylamines, 886—888 Protein Data Bank, 1087 Proteins... 

The general emphasis in this work is to compare the reactivity and selectivity of function-bearing micelles in catalysis with their simple counterparts. TThe pattern of research has been guided by the analogy of enzymic catalysis, and surfactants carrying the common prosthetic groups of protease enzymes have been synthesized. Most studies have been concerned with acyl transfer from reactive esters, and several authors have sought to demonstrate co-operativity between different catalytic sites. 

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