Norman Green made important and highly original contributions to the study of protein–protein interactions and interactions between proteins and biologically active small molecules. He established that the interaction between trypsin and several protein inhibitors was competitive with substrate rather than non-competitive as had been previously suggested. He also devised methods generally applicable to the measurement of kinetics of protein–protein interactions of very low dissociation constants. He showed that the hydroxylation of collagen proline was completed after its incorporation into the protein and before the collagen left the endoplasmic reticulum. This was followed by a decade of intensive research on the binding of biotin to avidin and the introduction of highly sensitive spectrophotometric techniques for the study of biotinyl enzymes. In particular, he made the important discovery that each of the four subunits of avidin bound its biotin independently of the occupancy of the other sites buried within the molecule, and that the quaternary structure of the protein was not essential for the formation of the binding site.
Dr Michael Green FRS died on 12 August 2019.
