Radiation Damage to Cytochrome c and Hemoglobin

Abstract

Radiation-induced damage to cytochrome c and hemoglobin has been defined by transformation into insoluble protein aggregates and scission products, radiolability of amino acids, and loss of biological redox or oxygen-binding properties. The insoluble aggregates are not formed by simple mechanisms involving cross-linking or denaturation of proteins. Radiation-induced hydrolysis of proteins per se is not the cause of scission. More complex mechanisms are suggested by the marked deviation in the amino acid pattern of these fractions from that of the original protein or TCA-precipitable protein. Methionine, histidine, phenylalanine, cystine, serine, and threonine are the most radiolabile amino acids in cytochrome c and hemoglobin.