Purification and partial characterization of human angiotensinogen

Area of Science:

• Biochemistry
• Proteomics
• Physiology

Background:

• Renin substrate is a key component of the renin-angiotensin system.
• Understanding its properties is crucial for studying blood pressure regulation.

Purpose of the Study:

• To purify human renin substrate from plasma.
• To characterize the purity, homogeneity, and biological activity of the purified substrate.

Main Methods:

• Ammonium sulfate precipitation
• Multiple chromatography techniques (Sephadex G-150, DEAE cellulose, calcium phosphate gel)
• Isoelectric focusing
• Preparative and analytical polyacrylamide gel electrophoresis (PAGE)
• Ouchterlony immunodiffusion and immunoelectrophoresis
• Gel filtration
• Amino acid analysis

Main Results:

• Achieved >95% purity of human renin substrate.
• Demonstrated homogeneity via analytical PAGE and immunological methods.
• Confirmed retained biological activity, with Km similar to native substrate.
• Determined molecular weight as 110,000 Da.
• Identified distinct amino acid composition compared to hog renin substrate.

Conclusions:

• A highly pure and biologically active human renin substrate was successfully isolated.
• The purified substrate is suitable for further biochemical and physiological studies.
• Differences in amino acid composition may indicate species-specific variations in renin substrate structure.