title: Histochemical demonstration of primary amino groups with 2-hydroxy-1-naphthaldehyde (HNA): optimization of the method.
abstract: 2-hydroxy-1-naphthaldehyde (HNA) was used for the histochemical demonstration of primary amino groups. The Schiff-bases formed exhibited a double-banded maximum absorption at lambda = 420 nm and lambda = 400 nm, respectively. The dependence of the equilibrium of the Schiff-base formation upon the concentration of HNA, the reaction medium, especially upon its pH-value, was investigated with Ehrlich ascites tumour cells and rat liver parenchymal cells. Optimum conditions were elaborated for the histochemical reaction running either in absolute ethanol (HNA-EtOH) or in a mixture of ethanol and acetate buffer pH = 4 (HNA-pH4), the equilibrium of the reactions adjusted after 10 d and 1 d, respectively. The HNA-pH4-method can be used for the histochemical demonstration of primary alpha-, delta-, and epsilon-amino groups of proteins. The HNA-EtOH-method comprises primary amino groups of proteins and of other substances insoluble in absolute ethanol. Both histochemical methods proved to be reproducible.
authors.affiliation: Institute of Biochemistry, University Graz, Austria.
authors.forename: G
authors.initials: G
authors.lastname: Nöhammer
mesh_terms: D000588:Amines / Q000032:analysis*; D000818:Animals; D002286:Carcinoma, Ehrlich Tumor / Q000473:pathology*; D004396:Coloring Agents; D006651:Histocytochemistry; D006652:Histological Techniques; D008099:Liver / Q000166:cytology*; D051379:Mice; D009281:Naphthalenes; D012545:Schiff Bases
chemical_list: D000588:Amines; D004396:Coloring Agents; D009281:Naphthalenes; D012545:Schiff Bases; C062247:2-hydroxy-1-naphthaldehyde