Key Points
- To characterize the molecular properties of inactive renin in normal and pregnancy plasma and elucidate the mechanism behind its activation.
- Measured renin activation in normal and pregnancy plasma following exposure to pH 3.3 or cold conditions.
- Estimated apparent molecular weights and charge characteristics using gel filtration and ion-exchange chromatography at pH 8.4.
- Subjected pregnancy plasma proteins to Concanavalin A-Sepharose affinity chromatography and tested reconstitution with pepsinogen before pH 3.3 dialysis.
- Inactive renin accounted for 76% of total renin in normal plasma and 93% in pregnancy plasma.
- Active renin demonstrated an apparent molecular weight of 43,000 in normal plasma versus 60,000 in pregnancy plasma, while inactive renin showed peaks at 62,000 and 46,000 in normal plasma and 60,000 in pregnancy plasma.
- Affinity chromatography on Concanavalin A-Sepharose prevented pH 3.3-mediated activation, which was subsequently restored by adding physiologic concentrations of pepsinogen.
Structured PICO
PPopulationHuman plasma (normal and pregnancy)
IInterventionIn vitro activation by pH 3.3 or cold, and biochemical characterization
OOutcomeBiochemical properties and activation mechanisms of inactive reninsurrogate
The study characterizes the biochemical properties of inactive renin in human plasma, highlighting its larger molecular weight and the role of pepsin in its activation.