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Isolation and characterization of human renin substrate
Japanese Circulation Journal
|April 1, 1980
Summary
Researchers purified human renin substrate (angiotensinogen) from plasma using multiple chromatography techniques. The purified protein was confirmed as homogeneous, revealing its glycoprotein nature and molecular weight.
Area of Science:
- Biochemistry
- Proteomics
- Renal Physiology
Background:
- Human renin substrate, also known as angiotensinogen, is a key precursor in the renin-angiotensin-aldosterone system.
- Understanding its biochemical properties is crucial for investigating blood pressure regulation.
Purpose of the Study:
- To purify and characterize human renin substrate from plasma.
- To determine the homogeneity, molecular weight, and biochemical composition of the purified protein.
Main Methods:
- Purification involved ammonium sulfate precipitation, DEAE-cellulose, Concanavalin A-Sepharose, Hydroxylapatite chromatography, isoelectric focusing, and gel filtration.
- Homogeneity was assessed using polyacrylamide gel electrophoresis (PAGE), SDS-PAGE, and analytical ultracentrifugation.
- Molecular weight was determined by sedimentation equilibrium studies.
Main Results:
- A 10% recovery of purified human renin substrate was achieved with a specific angiotensin I content of 10.5 µg/mg protein.
- Electrophoretic and ultracentrifugal analyses confirmed the homogeneity of the purified renin substrate.
- The protein was identified as a glycoprotein (13% carbohydrate) with a molecular weight of 60,900 Da and exhibited isoelectric point heterogeneity (pI 4.6 and 4.9).
- Cystine was not detected in the amino acid analysis.
Conclusions:
- A robust purification protocol for human renin substrate was established.
- The purified human renin substrate is a homogeneous glycoprotein with a defined molecular weight and characteristic heterogeneity.
- These findings provide a well-characterized protein for further studies on the renin-angiotensin system.