Effects of pargyline and diethyldithiocarbamate in vivo treatment on aldehyde dehydrogenase activities of submitochondrial fractions.

1) Aldehyde dehydrogenase with a Km for acetaldehyde in the micromolar range (referred to as low Km-AldDH) is located in the matrix and that with a Km in the millimolar range (referred to as high Km-AldDH) is located in both the matrix and the outer membrane of mitochondria. 2) Pargyline in vivo treatment (100 mg/kg i.p.) caused a complete inhibition of the low Km-AldDH activity of the matrix fraction but caused only a 10% inhibition of the high Km-AldDH activities of the matrix and the outer membrane fractions. Diethyldithiocarbamate (DDC) treatment (700 mg/kg i.p.) caused less than 80% inhibition of the low Km-AldDH activity of the matrix fraction and caused a 20% inhibition of the high Km-AldDH activity of the matrix fraction. DDC treatment had no effect on the enzyme activity of the outer membrane fraction. The difference in the degree of inhibition of the low Km-AldDH activity of the matrix fraction by pargyline and DDC treatment may cause different blood acetaldehyde levels during ethanol oxidation.