title: Reverse reaction of lysophosphatidylinositol acyltransferase. Functional reconstitution of coenzyme A-dependent transacylation system.
abstract: CoA-dependent transacylation activity in microsomes catalyzes the transfer of fatty acid between phospholipids and lysophospholipids in the presence of CoA without the generation of free fatty acid. We examined the mechanism of the transacylation system using partially purified acyl-CoA:lysophosphatidylinositol (LPI) acyltransferase (LPIAT) from rat liver microsomes to test our hypothesis that both the reverse and forward reactions of acyl-CoA:lysophospholipid acyltransferases are involved in the CoA-dependent transacylation process. The purified LPIAT fraction exhibited ATP-independent acyl-CoA synthetic activity and CoA-dependent LPI generation from PI, suggesting that LPIAT could operate in reverse to form acyl-CoA and LPI. CoA-dependent acylation of LPI by the purified LPIAT fraction required PI as the acyl donor. In addition, the combination of purified LPIAT and recombinant lysophosphatidic acid acyltransferase could reconstitute CoA-dependent transacylation between PI and phosphatidic acid. These results suggest that the CoA-dependent transacylation system consists of the following: 1) acyl-CoA synthesis from phospholipid through the reverse action of acyl-CoA:lysophospholipid acyltransferases; and 2) transfer of fatty acyl moiety from the newly formed acyl-CoA to lysophospholipid through the forward action of acyl-CoA:lysophospholipid acyltransferases.
authors.affiliation: Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa 199-0195, Japan. ayamashi@pharm.teikyo-u.ac.jp
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yamashita
authors.forename: Masanobu
authors.initials: M
authors.lastname: Watanabe
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Sato
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Miyashita
authors.forename: Tomonari
authors.initials: T
authors.lastname: Nagatsuka
authors.forename: Hironori
authors.initials: H
authors.lastname: Kondo
authors.forename: Norikazu
authors.initials: N
authors.lastname: Kawagishi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Nakanishi
authors.forename: Ryo
authors.initials: R
authors.lastname: Kamata
authors.forename: Takayuki
authors.initials: T
authors.lastname: Sugiura
authors.forename: Keizo
authors.initials: K
authors.lastname: Waku
mesh_terms: D000217:Acyltransferases / Q000737:chemistry* / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D003065:Coenzyme A / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005227:Fatty Acids / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology / Q000378:metabolism; D008956:Models, Chemical; D051381:Rats; D017208:Rats, Wistar; D013379:Substrate Specificity
chemical_list: D005227:Fatty Acids; D000255:Adenosine Triphosphate; D000217:Acyltransferases; C021522:lysophosphatidylinositol acyltransferase; C018764:2-acylglycerophosphate acyltransferase; D003065:Coenzyme A