Fluorescent demonstration of basement membranes with hydroxy-naphthoic acid hydrazide

The hydroxy-naphthoic acid hydrazide (HNAH) procedure can be employed not only for selective fluorochroming of side chain carboxyl groups of proteins, but also for demonstration of certain exoplasmic structures---particularly basement membranes. The demonstration of basement membranes by the HNAH procedure is likely related to the relatively high levels of available side chain carboxyl groups in the noncollagen glycoproteins of basement membranes.