Phosphatidic Acid Synthesis in Castor Bean Endosperm 1
AUTOR(ES)
Vick, Brady
RESUMO
Enzyme assays on organelles isolated from the endosperm of castor bean (Ricinus communis var. Hale) by sucrose density gradient centrifugation showed that palmitoyl-CoA:sn-glycerol 3-phosphate acyltransferase (EC 2.3.1.15) was localized in the membranes of the endoplasmic reticulum. Mn2+ was required for activity, but Ca2+ and Mg2+ could substitute for Mn2+ at higher concentrations. The apparent Km was 170 μm for sn-glycerol 3-phosphate and approximately 8 μm for palmitoyl-CoA. The optimum pH range was 7 to 7.5 and the principal reaction product was diacyl-sn-glycerol 3-phosphate (phosphatidic acid). Monoacyl-sn-glycerol 3-phosphate (lysophosphatidic acid) was not released as a free intermediate in the reaction. The maximum activity of the enzyme occurred immediately after imbibition, preceding the development of mitochondria and glyoxysomes.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=542424Documentos Relacionados
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