Journal of Lipid Research, Vol 20, 17-21, Copyright © 1979 by Lipid Research, Inc.
Evidence that cholic acid CoA ligase is located asymmetrically on the cytoplasmic surface of hepatic microsomal vesicles
MA Polokoff, RA Coleman and RM Bell
The cholic acid CoA ligase activity of rat liver was quantitatively
inactivated by proteolysis with pronase, chymotrypsin, subtilisin, or
proteinase K in intact microsomal vesicles. Under the conditions employed,
less than 14% of the lumenal mannose-6-phosphate phosphatase activity was
lost, and the mannose-6-phosphate phosphatase activity remained highly
latent. After microsomal integrity was disrupted with sodium deoxycholate,
protease treatment resulted in a loss of greater than 74% of the
mannose-6-phosphate phosphatase activity. Cholic acid CoA ligase activity
was unaffected by preincubation of microsomes with sodium taurocholate
under conditions that led to the complete expression of latent
mannose-6-phosphate phosphatase activity. The data suggest that cholic acid
CoA ligase activity is located on the cytoplasmic surface of hepatic
microsomal vesicles.