Aldehyde dehydrogenase isozymes in stomach autopsy specimens from Germans and Chinese

Human stomach aldehyde dehydrogenase (ALDH) isozymes were screened in random autopsy specimens from 66 North German and 33 Chinese individuals. Three ALDH isozymes were identified, which differed in their electrophoretic mobility, affinity to acetaldehyde, propionaldehyde, furfural, and to NAD+ as coenzyme as well as in inhibition by disulfiram, pH optimum and heat stability. While all the German stomach specimens showed ALDH I, ALDH II, and ALDH III isozymes, these isozymes were found in 68, 88, and 99% of the Chinese samples, respectively. The electrophoretic resolution of ALDH III into different activity bands is apparently due to the artefactual formation of secondary isozymes rather than to the existence of genetic variants.