ABSTRACT
The specific modification of tyrosyl residues in proteins has provided considerable information regarding the participation of these residues in the catalytic processes of enzymes as well as specific binding processes of proteins. There has also been considerable interest in the modification of tyrosyl residues to introduce spectral probes into proteins such as the modification of tyrosyl residues with aromatic diazonium compounds or tetranitromethane. There is considerable literature concerning the reaction of tyrosyl residues with aromatic diazonium compounds. The extent of the formation of monoazotyrosyl and monoazohistidyl derivatives is determined by spectral analysis. Iodination is somewhat infrequently used for the modification of tyrosyl residues in protein. The modification of tyrosyl residues in phosphoglucomutase by iodination has been reported. Iodination of tyrosyl residues can also be accomplished with iodine monochloride at mildly alkaline pH. Tyrosyl residues in proteins are also modified by reaction with cyanuric fluoride.
