Triacylglycerol synthesis in goat mammary gland. The effect of ATP, Mg2+ and glycerol 3-phosphate on the esterification of fatty acids synthesized de novo.
Goat mammary-gland microsomal fraction by itself induces synthesis of medium-chain-length fatty acids by goat mammary fatty acid synthetase and incorporates short- and medium-chain fatty acids into triacylglycerol. Addition of ATP in the absence or presence of Mg2+ totally inhibits triacylglycerol synthesis from short- and medium-chain fatty acids, and severely inhibits synthesis de novo of medium-chain fatty acids. The inhibition by ATP of fatty acid synthesis and triacylglycerol synthesis de novo can be relieved by glycerol 3-phosphate. The effect of ATP could not be mimicked by the non-hydrolysable ATP analogue, adenosine 5'-[beta,gamma-methylene]triphosphate and could not be shown to be caused by inhibition of the diacylglycerol acyltransferase by a phosphorylation reaction. Possible explanations for the mechanism of the inhibition by ATP are discussed, and a hypothetical model for its action is outlined.
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D004951:Esterification; D064429:Fatty Acid Synthases / Q000378:metabolism; D005227:Fatty Acids / Q000096:biosynthesis*; D005260:Female; D005994:Glycerophosphates / Q000494:pharmacology; D006041:Goats; D066298:In Vitro Techniques; D007774:Lactation; D008274:Magnesium / Q000494:pharmacology; D008321:Mammary Glands, Animal / Q000187:drug effects / Q000378:metabolism*; D008861:Microsomes / Q000187:drug effects / Q000378:metabolism; D011247:Pregnancy; D014280:Triglycerides / Q000096:biosynthesis*
D005227:Fatty Acids; D005994:Glycerophosphates; D014280:Triglycerides; C005147:5'-adenylyl (beta,gamma-methylene)diphosphonate; D000255:Adenosine Triphosphate; C029620:alpha-glycerophosphoric acid; D064429:Fatty Acid Synthases; D008274:Magnesium; C002630:alpha,beta-methyleneadenosine 5'-triphosphate