Probing the active site of cytoplasmic aldehyde dehydrogenase with a chromophoric reporter group.

High concentrations of aldehydes slow the reaction of cytoplasmic aldehyde dehydrogenase with thiol-group modifiers.

High concentrations of aldehydes slow the inactivation of cytoplasmic aldehyde dehydrogenase by disulfiram and also slow the reaction of the enzyme with 2,2'-dithiodipyridine. It is concluded that a low-affinity aldehyde-binding site is probably the site at which thiol-group modifiers react with aldehyde dehydrogenase, as well as being the active site for hydrolysis of 4-nitrophenyl acetate.

Studies of the esterase activity of cytosolic aldehyde dehydrogenase with resorufin acetate as substrate.

Resorufin acetate is a very good substrate for sheep liver cytosolic aldehyde dehydrogenase, both from the point of view of practical spectrophotometry and in terms of information provided about the nature of the catalysis shown by this enzyme. p-Nitrophenyl (PNP) acetate competes against resorufin acetate for the enzyme's active site (although relatively weakly as the latter substrate has the ...

PROBING THE ACTIVE SITE OF RHODANESE WITH DISULFIDE REAGENTS

A comparison of nitrophenyl esters and lactones as substrates of cytosolic aldehyde dehydrogenase.

1. p-Nitrophenyl (PNP) acetate and propionate show a burst of p-nitrophenoxide release when their hydrolysis is catalysed by sheep liver cytosolic aldehyde dehydrogenase. This is not seen in the presence of NAD+ or NADH, implying a change in ratedetermining step. 2. 6-Nitrodihydrocoumarin (6-NDC) shows no burst of absorbance in the visible region. We propose that the pKa of the transient "repor...

Automatic classification of highly related Malate Dehydrogenase and L-Lactate Dehydrogenase based on 3D-pattern of active sites

Accurate protein function prediction is an important subject in bioinformatics, especially wheresequentially and structurally similar proteins have different functions. Malate dehydrogenaseand L-lactate dehydrogenase are two evolutionary related enzymes, which exist in a widevariety of organisms. These enzymes are sequentially and structurally similar and sharecommon active site residues, spati...