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Characterization of different high molecular weight angiotensinogen forms
Ahmed Ramaha1, Jérôme Célérier, Philip A Patston
1Department of Oral Medicine and Diagnostic Sciences, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
American Journal of Hypertension
|June 12, 2003
Summary
High molecular weight angiotensinogen forms were identified in normal plasma. These polymers may help understand their role in conditions like hypertension.
Area of Science:
- Biochemistry
- Proteomics
Background:
- Angiotensinogen is key to the renin-angiotensin system, regulating blood pressure.
- Defects in this system are linked to hypertension.
- High molecular weight (HMW) angiotensinogen, unlike the native 62,000-dalton monomer, is poorly characterized but increases significantly in pregnancy and hypertension.
Purpose of the Study:
- To investigate the characteristics of HMW angiotensinogen in normal human plasma.
- To understand the polymerization of angiotensinogen.
Main Methods:
- Gel filtration chromatography and Western blotting were used to detect HMW angiotensinogen.
- Ion-exchange chromatography was employed for further purification.
- Sodium dodecyl sulfate (SDS) and native gel electrophoresis analyzed in vitro polymerization.
Main Results:
- Two distinct HMW angiotensinogen forms were detected with molecular weights of 500,000 and 250,000 daltons (gel filtration).
- SDS-PAGE revealed non-reduced molecular weights of 140,000 and 110,000 daltons, and 62,000 daltons under reduced conditions.
- Angiotensinogen's polymerization characteristics align with its classification within the serpin protein family.
Conclusions:
- In vitro polymerized angiotensinogen may serve as a model for in vivo HMW forms.
- Further research into these polymers can elucidate their physiological functions.