Immunodepletion experiments suggest that acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT-1) protein plays a major catalytic role in adult human liver, adrenal gland, macrophages, and kidney, but not in intestines.
The first acyl-coenzyme A:cholesterol acyltransferase (ACAT) cDNA cloned and expressed in 1993 is designated as ACAT-1. In various human tissue homogenates, ACAT-1 protein is effectively solubilized with retention of enzymatic activity by the detergent CHAPS along with high salt. After using anti-ACAT-1 antibodies to quantitatively remove ACAT-1 protein from the solubilized enzyme, measuring the residual ACAT activity remaining in the immunodepleted supernatants allows us to assess the functional significance of ACAT-1 protein in various human tissues. The results showed that ACAT activity was immunodepleted 90% in liver (83% in hepatocytes), 98% in adrenal gland, 91% in macrophages, 80% in kidney, and 19% in intestines, suggesting that ACAT-1 protein plays a major catalytic role in all of the human tissue/cell homogenates examined except intestines. Intestinal ACAT activity is largely resistant to immunodepletion and is much more sensitive to inhibition by the ACAT inhibitor Dup 128 than liver ACAT activity.
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Department of Biochemistry, Dartmouth Medical School, Hanover, NH 03755, USA.
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D000293:Adolescent; D000311:Adrenal Glands / Q000201:enzymology*; D000328:Adult; D002793:Cholic Acids; D003902:Detergents; D006801:Humans; D015151:Immunoblotting; D007422:Intestines / Q000201:enzymology; D007668:Kidney / Q000201:enzymology*; D008099:Liver / Q000201:enzymology*; D008264:Macrophages / Q000201:enzymology*; D008875:Middle Aged; D012995:Solubility; D002785:Sterol O-Acyltransferase / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D014018:Tissue Distribution
D002793:Cholic Acids; D003902:Detergents; D002785:Sterol O-Acyltransferase; C028213:3-((3-cholamidopropyl)dimethylammonium)-1-propanesulfonate