Comparison of physico-chemical properties of two forms of dopamine-beta-hydroxylase from chromaffin granules

• Published in: Biokhimiia (Moscow, Russia) Vol. 46; no. 4; p. 635
• Main Authors: Boiadzhan, A S, Nalbandian, R M, Buniatian, G Kh
• Format: Journal Article
• Language: Russian
• Published: Russia (Federation) 01-04-1981
• Subjects: Animals; Binding Sites; Cattle; Chromaffin Granules - enzymology; Chromaffin System - enzymology; Copper - analysis; Dopamine beta-Hydroxylase - isolation & purification; Dopamine beta-Hydroxylase - metabolism; Electron Spin Resonance Spectroscopy; Hydrogen-Ion Concentration; Isoenzymes - isolation & purification; Isoenzymes - metabolism; Kinetics; Osmolar Concentration; Protein Binding; Protein Conformation
• ISSN: 0320-9725

The purification procedures of both soluble and membrane-bound forms of dopamine-beta-hydroxylase have been developed. The membrane-bound form was solubilized by a detergent. Both preparations have been obtained in electrophoretically homogeneous form. The yield of soluble and membrane-bound enzyme forms by a described procedure was 22 mg and 15 mg, correspondingly, from 100 g of chromaffin granules paste. A comparative analysis of the main physico-chemical properties of the two enzyme forms has shown their identity. The effects of pH, ionic strength, oxidants and reducers on the EPR spectra of the two forms of dopamine-beta-hydroxylase have been investigated. A comparison of the EPR spectra of the two forms of the enzyme suggests that the copper environment of soluble and membrane-bound dopamine-beta-hydroxylases is practically identical.