The cross-linking of tyrosine by treatment with tetranitromethane.

1. Tyrosine was treated with tetranitromethane. 2. Approx. 10% of the tyrosine was converted into 3-nitrotyrosine. 3. Three fluorescent compounds were also formed. They appear to be a dimer, trimer and tetramer in which tyrosine units are linked by biphenyl bonds. 4. The dimer and trimer have also been isolated from some proteins after treatment with tetranitromethane. 5. The yield of 3-nitrotyrosine from ovotransferrin after treatment with tetranitromethane was much smaller than the loss of tyrosine. 6. Several unidentified compounds were also formed by the reaction between tyrosine and tetranitromethane.