Work

THE INHIBITION OF d-AMINO ACID OXIDASE BY DESOXYCORTICOSTERONE

Year: 1950

Type: article

Abstract: In the course of investigations in these laboratories on the effect of steroid hormones on various enzymatic systems, it was noted that desoxycorticosterone exerted a greater inhibitory effect than other steroids, and that the n-amino acid oxidase system was particularly strongly affected.This paper deals with experiments elucidating in part the characteristics of the n-amino acid oxidasc-desoxycorticosterone inhibition, the effect of other steroids on this enzyme system, and the extent of desoxycorticosterone inhibition on other enzymatic reactions. Methods and MaterialsPreparation of n-Amino Acid Oxidase-The source of n-amino acid oxidase was an acetone powder of pig kidney prepared as follows: Fresh pig kidneys were chilled, deprived of fatty tissue, and ground twice through a medium pore meat grinder.The mince was added to 20 volumes of acetone at -lo', stored for 1 hour in a cold room at l", and filtered through a Biichner funnel, and the residue washed with cold acetone.The coarse powder thus obtained was spread out on paper towels and dried in air until all odor of acetone had disappeared.The final drying was carried out in a vacuum desiccator over phosphorus pentoxide.The powder was stored at -10" and a fresh aqueous extract of the enzyme was prepared for use just prior to each experiment. 1 to 2 gm. of acetone powder were ground in a mortar with 15 ml. of ice-cold water and allowed to stand for 10 minutes with stirring.The aqueous extract was centrifuged for 5 'minutes to remove any coarse particles and the opaque supernatant fluid added to Warburg flasks containing cold medium and substrates.All operations were carried out in the cold.An aqueous extract of 80 mg. of this powder, representing about 0.7 mg. of N, took up 180 ~1. of oxygen in the presence of 0.04 M nn-alanine per 60 minutes of incubation.Tissue blanks showed no oxygen uptake.Nitrogen determinations were carried out with the use of a Kjeldahl apparatus.

Source: Journal of Biological Chemistry

DOI: 10.1016/s0021-9258(18)56253-0

Authors: Mika. Hayano, Ralph I. Dorfman, Edward Y. Yamada

Institution: Case Western Reserve University

Language: English

Topic: Amino Acid Enzymes and Metabolism

Subfield: Biochemistry

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $3,430