Year: 1974
Type: article
Abstract: Resealed chromaffin-granule ;ghosts' were used to study the steady-state kinetics of catecholamine transport. The pump has a high affinity for (-)-noradrenaline, (-)-adrenaline, tyramine and 5-hydroxytryptamine (serotonin), but a lower affinity for (+)-noradrenaline. The measured rates of incorporation do not conform to Michaelis-Menten kinetics, but affinity constants for the former substrates are in the range 8-18mum. Reserpine is a potent inhibitor. Incorporation as a function of ATP concentration also fails to show simple kinetics; the affinity constant for ATP is deduced to be about 3mm at 1mm-MgCl(2). Adenylyl (betagamma-methylene)diphosphonate is a competitive inhibitor at low concentrations, but inhibits more strongly at high concentrations. The pump has a transition temperature at 29 degrees C and does not seem to be identical with the Mg(2+)-stimulated adenosine triphosphatase of chromaffin granules.
Source: Biochemical Journal
DOI: 10.1042/bj1440319
Author: J H Phillips
Institutions: MRC Laboratory of Molecular Biology, Medical Research Council
Language: English
Subfield: Cell Biology
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W2340343084