Prooxidant Action of Crystalline Serum Albumin in Lipid Peroxidation during Incubation of Rat Adipose Tissue in Vitro.

During in vitro incubation of rat adipose tissue in a medium containing crystalline serum albumin, a thiobarbituric acid-reacting chromogen (presumably malonaldehyde) appears in the medium, reflecting peroxidation of polyunsaturated fatty acids in the tissue. Albumin which has been dialyzed, treated with EDTA and dialyzed, or subjected to gel filtration shows a markedly decreased ability to support malonaldehyde production. Prooxidant activity is found in the dialysate and in protein-free fractions appearing after albumin in the gel filtration. The prooxidant that contaminates albumin has been identified as iron and citrate, the latter acting by forming a soluble complex with the iron.