Thioredoxin-linked lipid hydroperoxide peroxidase activity of human serum albumin in the presence of palmitoyl coenzyme A.
Human Serum Albumin (HSA) exerted a significant lipid peroxidase activity with the use of a thiol-reducing equivalent such as dithiothreitol (DTT). Carboxyl group-modified HSA (CM-HSA) showed a 10-fold stronger lipid peroxidase activity (1.6 nmol/min/mg) than that of HSA (0.17 nmol/min/mg). Instead of DTT, thioredoxin (Trx) also supported reducing equivalent to the reduction of lipid hydroperoxide by CM-HSA. Contrast to CM-HSA, HSA did not reduce lipid peroxide with the use of Trx. In the presence of palmitoyl coenzyme A (palmitoyl-CoA) however, HSA used Trx as an electron donor to the reduction of lipid hydroperoxide. The Trx-linked peroxidase activity of HSA sharply increased with elongation in the carbon chain of the acyl moiety of acyl-CoA, showing an optimum activity in the presence of palmitoyl-CoA. Fluorescence study indicates the conformational changes of HSA induced by palmitoyl-CoA. Together, these data suggest that palmitoyl-CoA-bound HSA has a capability to remove lipid peroxide with the use of electrons given by Trx system.
Lee
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Department of Biochemistry, Paichai University, 439-6 Doma-2 Dong Seo-Gu Taejon 302-735, Republic of Korea.
Kim
I H
IH
D004229:Dithiothreitol / Q000494:pharmacology; D006801:Humans; D008041:Linoleic Acids / Q000378:metabolism; D008054:Lipid Peroxides / Q000378:metabolism*; D010084:Oxidation-Reduction; D010171:Palmitoyl Coenzyme A / Q000494:pharmacology*; D010544:Peroxidases / Q000097:blood*; D012709:Serum Albumin / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013879:Thioredoxins / Q000097:blood*
D008041:Linoleic Acids; D008054:Lipid Peroxides; D012709:Serum Albumin; D010171:Palmitoyl Coenzyme A; C008285:linoleic acid hydroperoxide; D013879:Thioredoxins; D010544:Peroxidases; D004229:Dithiothreitol