title: Effect of unsaturated fatty acids on protoporphyrinogen oxidation, a step in heme and chlorophyll synthesis in plant organelles.
abstract: Oleic acid stimulates enzymatic protoporphyrinogen oxidation by extracts of barley mitochondria and etioplasts. Greater stimulation occurred with Triton X-100 extracts which had been passed over a Sephacryl S-200 column than with crude Triton extracts, suggesting that purification may have removed a lipid factor required for optimal enzymatic activity. Palmitic acid, various phospholipids and detergents, or esters and alcohols of oleic acid did not substitute for free oleic acid. Linoleic acid caused a greater stimulation of protoporphyrinogen oxidation in both crude and purified barley organelle extracts and also caused a slow chemical oxidation of protoporphyrinogen. The stimulating effect of unsaturated fatty acids on enzymatic protoporphyrinogen oxidation may indicate a lipid requirement for this membrane bound enzyme or may also indicate involvement of unsaturated lipid oxidation in plant protoporphyrinogen oxidation.
mesh_terms: D002734:Chlorophyll / Q000096:biosynthesis*; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D006418:Heme / Q000096:biosynthesis*; D001467:Hordeum / Q000378:metabolism; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000494:pharmacology; D008928:Mitochondria / Q000378:metabolism; D019301:Oleic Acid; D009829:Oleic Acids / Q000494:pharmacology; D009940:Organoids / Q000378:metabolism*; D010084:Oxidation-Reduction; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000494:pharmacology; D010944:Plants / Q000378:metabolism*; D011166:Porphyrins / Q000378:metabolism*; D011524:Protoporphyrins / Q000378:metabolism*
chemical_list: D005231:Fatty Acids, Unsaturated; D008041:Linoleic Acids; D009829:Oleic Acids; D010169:Palmitic Acids; D011166:Porphyrins; D011524:Protoporphyrins; D002734:Chlorophyll; D019301:Oleic Acid; D019308:Palmitic Acid; D006418:Heme; C011539:protoporphyrinogen; D019787:Linoleic Acid