ISSN:
1573-4919
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
,
Chemie und Pharmazie
,
Medizin
Notizen:
Summary 1. Two different molecular forms of dopamine-β-hydroxylase were isolated from human serum; a major component (Peak I enzyme) with a molecular weight of 368000 and with a higher specific activity and a minor component (Peak II enzyme) with a molecular weight of 188000 and with a lower specific activity. 2. Both forms require ascorbic acid for the activity, and are stimulated by fumarate. Addition of n-ethylmaleimide or copper also increased the activity. The optimal pH of both forms in the presence of 20mm tyramine as substrate is 5.0. 3. Km values toward tyramine of Peak I enzyme and Peak II enzyme were 1.67mm and 14.2mm, respectively. 4. Both Peak I enzyme and Peak II enzyme are glycoprotein.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00280277
Permalink