PURIFICATION AND CHARACTERIZATION OF THIOL-SPECIFIC ANTIOXIDANT PROTEIN FROM HUMAN RED-BLOOD-CELL - A NEW-TYPE OF ANTIOXIDANT PROTEIN

A thiol-specific antioxidant protein (Protector Protein, PRP) was puri fied from human red blood cells (RBC). The PRP exists as a predominant protein in human RBC, which showed distinct thiol-specific antioxidan t activities in the presence of dithiothreitol (DTT) as a reducing equ ivalent, The human RBC PRP (HRPRP) completely inhibited visible absorp tion spectral changes of oxyhemoglobin, DNA cleavage, and the peroxida tion of RBC membrane by a nonenzymatic Fe3+/O-2/thiol mixed-function o xidation system capable of generating hydroxyl radical. These observat ions suggest that HRPRP could act as a new type of antioxidant protein to maintain the RBC integrity by scavenging reactive oxygen species. (C) 1994 Academic Press, Inc.