Fluorescence of 2-hydroxy-3-naphthoic acid hydrazide derivatives of side-chain carboxyl groups of proteins

Summary Sections processed through the first part of the Barrnett and Seligman (1958) procedure, which is considered to be selective for side-chain carboxyl groups of proteins, are fluorescent when exposed to incident blue light. The results of a number of tests suggest that the fluorescence can be ascribed principally to binding of 2-hydroxy-3-naphthoic acid hydrazide (HNAH) by mixed acid anhydride derivatives of side-chain carboxyl groups of proteins. Thus, the procedure appears to be a fluorescent counterpart of the bright-field method of Barrnett and Seligman.