Human placental chorionic renin: production, purification and characterization

Area of Science:

• Biochemistry
• Molecular Biology
• Endocrinology

Background:

• Renin is a key enzyme in the renin-angiotensin system, regulating blood pressure.
• Human chorionic trophoblasts are a source of prorenin, the inactive precursor to renin.

Purpose of the Study:

• To purify and characterize native human renin from chorionic trophoblasts.
• To compare chorionic renin with human kidney renin.

Main Methods:

• Five-step purification scheme including ammonium sulfate fractionation, ion-exchange and affinity chromatography, and gel filtration.
• Enzyme activity assays (Goldblatt Units/mg).
• Molecular weight determination (SDS-PAGE), amino acid composition, N-terminal sequencing, and isoelectric focusing.

Main Results:

• Milligram quantities of homogeneous human renin were purified from chorionic trophoblast cultures.
• Chorionic prorenin (43,000 Da) and active renin (40,000 Da) were characterized as single polypeptide chains.
• Specific activity was 1072 Goldblatt Units/mg, and the enzyme's amino acid composition and N-terminal sequence were identical to human kidney renin.
• Isoelectric focusing revealed microheterogeneity in chorionic renin.

Conclusions:

• Native human renin can be purified to homogeneity from chorionic trophoblasts.
• Chorionic renin shares identical biochemical properties with kidney renin, suggesting a common structure and function.
• The findings provide a basis for further investigation into the physiological roles of chorionic renin.