Kwan-Chung Tsou

HISTOCHEMICAL DEMONSTRATION OF β-d-GLUCURONIDASE WITH A SYNTHETIC SUBSTRATE

The synthesis of a substrate, 6-bromo-2-naphthyl β-d-glucopyruronoside, is described, and the procedure for the histochemical demonstrations of β-d-glucuronidase activity and experiments to determine the reliability of the results of localization of enzymatic activity are given. The results in normal tissues of the rat are presented. Greatest concentration of enzymatic activity was seen in liver, spleen, epithelium of gastrointestinal tract, uterus, thyroid, and in the white matter of the nervous system.

The colorimetric determination of leucine aminopeptidase activity with l-leucyl-β-naphthylamide hydrochloride☆

Abstract The synthesis of l -leucine-β-naphthylamide hydrochloride as a colorimetric substrate for the determination of leucine aminopeptidase is described along with the synthesis of optical isomers and other derivatives designed to clarify the specificity of the substrate. β-Naphthylamine, the product of enzymatic hydrolysis of the substrate, was determined either by a direct coupling method or by the use of the Bratton-Marshall procedure. The kinetics of the reaction were investigated and evidence for the specificity of the substrate was obtained. The distribution of enzymatic activity in mammalian tissue was investigated. A method was developed for the determination of leucine aminopeptidase in serum. The sera from pregnant women showed abnormally high values.

Histochemical demonstration of protein-bound amino groups.

A method for the histochemical demonstration of protein-bound amino groups is described. The method is based upon the reaction of primary amino groups with aldehydes to form Schiff bases. By the use of 3-hydroxy-2-naphthaldehyde, a red to blue azo dye is formed at the sites of reactivity in fixed tissue sections, after coupling with tetrazotized diorthoanisidine. Preparations of the reagent, histochemical procedure, evidence for the specificity of the reaction and the results of its application to normal rat tissues are given.

DEVELOPMENT OF A HISTOCHEMICAL METHOD FOR α-d-GALACTOSIDASE AND ITS DISTRIBUTION IN THE RAT

A histochemical method for the demonstration of α-d-galactosidase activity in formalinfixed, frozen sections was developed by the synthesis of 6-bromo-2-naphthyl-α-d-galactopyranoside. The histochemical procedure is similar to that developed for other glycosidases and utilizes the post-incubation coupling principle. A survey of the organs of the rat revealed the highest activity in the cytoplasm of epithelial cells of Brunners glands of the intestine, distal segment of proximal tubules of the kidney, thyroid and parathyroid glands and very strikingly in heterophiles and megakaryocytes.

A method for the colorimetric determination of α-d-glucosidase with a chromogenic substrate☆

Abstract A method has been developed for the assay of α- d -glucosidase activity in mammalian tissue and serum with 6-bromo-2-naphthyl α- d -glucopyranoside as substrate. The effects of the type and concentration of buffer, pH, incubation time, and concentration of tissue and substrate on the rate of enzymic hydrolysis are presented. The tissues of the rat were more active than those of the dog. The highest enzymic activity in both animals was found in the kidney and small intestine.