[Kinetic characteristics of enzymes of ethanol metabolism in rats]

Experimental animals were separated as for narcotic sleep length into short-sleeping and long-sleeping rat groups and as for alcohol motivation to rats preferring ethanol or water or an intermediate group as well. Alcohol- and aldehyde dehydrogenase reaction maximum speed as well as Michaelis-Menten constants for these enzymes were measured for each of these groups. Alcohol dehydrogenase affinity to cofactor in the reverse reaction was an order of magnitude higher as compared with the affinity to substrate in all the animal groups. Apparent Michaelis-Menten constant values were 1.5-2 times higher in short-sleeping and ethanol preferring rats in the direct reaction. There were no such differences for the reverse reaction. Alcohol dehydrogenase reaction maximum speed for short-sleeping group is close to that for animals preferring ethanol or water. For different forms of aldehyde dehydrogenase an increase of the apparent maximum speeds was distributed as follows: water preferring group < intermediate group < ethanol preferring group. Aldehyde dehydrogenase-1 Michaelis-Menten apparent constants for acetaldehyde were changed in the same way. Thus, data obtained suggest that ethanol metabolism speed along the path alcohol/aldehyde dehydrogenases are close in ethanol-preferring and short-sleeping rats.