The role of cytochrome b5 in delta 12 desaturation of oleic acid by microsomes of safflower (Carthamus tinctorius L.).
The electron donors for the membrane-bound fatty acid desaturases of higher plants have not previously been identified. In order to assess the participation of cytochrome b5 in microsomal fatty acid desaturation, the cytoplasmic domain of microsomal cytochrome b5 was purified from Brassica oleracea, and murine polyclonal antibodies were prepared. The IgG fraction from ascites fluid inhibited 62% of NADH-dependent cytochrome c reduction in safflower (Carthamus tinctorius L.) microsomes. These antibodies also blocked desaturation of oleic acid to linoleic acid in lipids of C. tinctorius microsomes by 93%, suggesting that cytochrome b5 is the electron donor for the delta 12 desaturase.
Kearns
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EV
Genetics Program, Michigan State University, East Lansing 48824.
Hugly
S
S
Somerville
C R
CR
D002250:Carbon Radioisotopes; D003579:Cytochrome Reductases / Q000378:metabolism*; D042966:Cytochrome-B(5) Reductase; D004579:Electron Transport; D044943:Fatty Acid Desaturases / Q000378:metabolism*; D007074:Immunoglobulin G / Q000276:immunology; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000378:metabolism; D008861:Microsomes / Q000201:enzymology*; D019301:Oleic Acid; D009829:Oleic Acids / Q000276:immunology / Q000378:metabolism*; D010944:Plants / Q000201:enzymology*; D012450:Safflower Oil / Q000378:metabolism*
D002250:Carbon Radioisotopes; D007074:Immunoglobulin G; D008041:Linoleic Acids; D009829:Oleic Acids; D019301:Oleic Acid; D012450:Safflower Oil; D019787:Linoleic Acid; D044943:Fatty Acid Desaturases; D003579:Cytochrome Reductases; D042966:Cytochrome-B(5) Reductase