Binding of styrene oxide to amino acids, human serum proteins and hemoglobin.

The covalent binding of 3H-styrene oxide to amino acids, and whole human blood was investigated in vitro. After reaction, serum, and red cells were separated, and proteins were digested into amino acids; styrene oxide derivatives were isolated by HPLC. The order of binding to free amino acids was cysteine much greater than histidine greater than lysine greater than serine. In serum proteins and hemoglobin cysteine-derivatives predominated. When styrene oxide was reacted with free cysteine and with proteins two isomers were observed. These were likely to present binding through the alpha and beta carbon of styrene oxide, and their abundance was about 2:1.