Liver cytosolic aldehyde dehydrogenase activity in the pregnant mouse

A 3-fold increase in aldehyde dehydrogenase (A1DH) was found in the cytosolic fraction of mouse liver homogenates during pregnancy. The increase in A1DH activity began at day 10 of pregnancy, peaked at parturition, and declined in a biphasic manner with half-lives of 4.15 and 47.7 days. Enzymes from control (beta A1DH), pregnant (pi A1DH) and phenobarbital-treated (phi AlDH) were partially purified and compared. All had molecular weights of approximately 60,000 daltons. Substrate specificities were similar except that phi A1DH had a lower Km for propionaldehyde than beta or pi and both pi and phi oxidized 4-carboxybenzaldehyde poorly compared to beta. Electrophoretic and thermal denaturation studies showed some similarities between beta and pi, but phi A1DH behaved quite differently. It was concluded that pregnancy caused an increase in one of the A1DHs already present in control mice, while phenobarbital treatment resulted in induction of a unique cytosolic A1DH.