Dehydrogenases carboxymethylation

Tris Acryl DEAE M (weak anion exchange) Carboxymethyl starch Lactate dehydrogenase (LDH) from beef heart 28... 

Inactivation of alcohol dehydrogenase from yeast with 14C-labeled [3-(3-bromoacetylpyridinio)-propyl]-adenosine pyrophosphate followed by oxidation showed the presence of 1-carboxymethyl histidine66. After inactivation of the enzyme with labeled [3-(4-bromoacetylpyridinio)-propyl]-adenosine pyrophosphate followed by oxidation, S-carboxymethyl cysteine was identified in the protein. In the case of glyceraldehyde-3-phosphate dehydrogenase, treatment with either coenzyme analogue leads to the modification of the cysteine residue. Treatment with [14C]nicotinamide-5-bromo-4-methylimidazole dinucleotide did not reveal any modified amino-acid-residues. The labeled nicotinamide residue split off during the recovery of the inactivated enzyme. Attempts to synthesize an inactivator labeled with a 14C-acetyl residue did not give satisfactory yields. If the enzyme-coenzyme derivative was treated with tritiated sodium boron hydride, tritium could be introduced (Fig. 22). Studies with... 

LADHee and that the activity disappeared after carboxymethylation of a cysteine residue at the active site of LADH s [145]. In a recent study by Okuda and Okuda it was demonstrated that the -hydroxysteroid dehydrogenase activity in human liver was associated with a major isoenzyme of liver alcohol dehydrogenase (/82, 2) that the activity was inhibited by a chelating agent for Zn, which resides in the active site of the enzyme [146], Kinetic studies with the highly purified isoenzyme showed that neither a Theorell-Chance mechanism nor a simple ordered BiBi mechanism applied to the reaction. Evidence was obtained that the reaction was asymmetric in both directions. It has been established by Fukuba that the 4A-hydro-gen in NADH is involved [147]. 

The inactivated carboxymethylated enzyme still binds NAD 85) and also has a small residual enzymic activity 144)- Reactive cysteine residues also occur in other dehydrogenases and have been compared 145), but the properties are different and these comparisons have no functional or evolutionary significance 2,73). 

Ribonuclease B, globin, R17-bacteriophage coat protein, carboxymethylated protein, subunits from BI component of TYMV tryptic digest of glyceraldehyde 3-phosphaie dehydrogenase of yeast Dipeptides with Leu/Ile as N-terminal residues Several di- and tri-peptides (see Table 2)... 

A. Fiori, M. Costa and E. Barboni. Oxidation of S-carboxymethyl-cysteine by glutamate dehydrogenase. Physiol. Chem. Phys.,... 

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