Human brain aldehyde dehydrogenase: activity with DOPAL and isozyme distribution

Aldehyde dehydrogenase (ALDH, EC 1.2.1.3), has been shown to be the most important enzyme for DOPAL metabolism in human brain (Agarwal et al.). In the present investigation cerebellum, corpus striatum and pons showed the highest ALDH activity. Most of the enzyme activity was found in the mitochondrial and microsomal fractions. Two activity bands on IEF gels and dual Km values indicate the presence of two distinct isozymes in all the fractions. Two cerebella from alcoholics yielded the same results as the control group regarding their total ALDH activity, subcellular distribution pattern and protein content. The presence of DOPAC (acid metabolite of DOPAL), pargyline, pyrazole or ethanol in the assay mixture did not alter the ALDH activity significantly.