Coenzyme A-dependent cleavage of membrane phospholipids in several rat tissues: ATP-independent acyl-CoA synthesis and the generation of lysophospholipids.
Biochim Biophys Acta
; 1255(2): 167-76, 1995 Mar 16.
Article
en En
| MEDLINE
| ID: mdl-7696331
ABSTRACT
Substantial amounts of acyl-CoA were formed when microsomes from several rat tissues were incubated with varying concentrations of free CoA and bovine serum albumin even in the absence of ATP and Mg2+. For instance, 86 nmol of acyl-CoA was produced when microsomes (5 mg protein) were incubated with 300 microM CoA for 30 min. It was calculated that 1.8% of total fatty acyl residues were converted to acyl-CoA during the incubation. No appreciable amount of acyl-CoA was formed from free fatty acid or from boiled microsomes under the same experimental conditions. These observations indicate that acyl-CoA is formed from microsomal lipids by an enzyme activity distinct from previously known long-chain fatty acyl-CoA synthetase. The apparent Km value for CoA and Vmax were 180 microM and 20 nmol/30 min per mg protein, respectively. We found that several species of acyl-CoA such as arachidonoyl-CoA were preferentially synthesized through the reaction and that several types of phospholipids actually act as acyl donors in the formation of acyl-CoA. Phosphatidylinositol and phosphatidylcholine appear to be preferred substrates. We confirmed that lysophosphatidylinositol and lysophosphatidylcholine were generated along with the formation of acyl-CoA. It seems very likely that CoA-mediated cleavage of phospholipids/ATP-independent acyl-CoA synthesis is implicated in the metabolism of certain types of fatty acyl residues of membranous phospholipids in mammalian cells.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Fosfolípidos
/
Acilcoenzima A
/
Lisofosfolípidos
/
Adenosina Trifosfato
/
Coenzima A
/
Lípidos de la Membrana
Límite:
Animals
Idioma:
En
Revista:
Biochim Biophys Acta
Año:
1995
Tipo del documento:
Article
País de afiliación:
Japón