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Apparent molecular size difference between plasma and renal inactive renins.
Summary
Human plasma and kidney inactive renins share similarities but differ in molecular size. Differences in carbohydrate composition may explain the observed size discrepancy in glycoproteins.
Area of Science:
- Biochemistry
- Renal Physiology
Background:
- Inactive renin from human plasma and kidney exhibits similarities.
- A key difference noted is their apparent molecular size.
Purpose of the Study:
- To investigate the molecular weight difference between plasma and renal inactive renins.
- To explore potential reasons for the observed size discrepancy.
Main Methods:
- Apparent molecular weights were determined using gel filtration with radiolabeled standards.
- Trypsin activation in the presence of benzamidine and albumin was employed for detection.
- Concanavalin A-Sepharose chromatography was used to assess glycoprotein nature.
Main Results:
- Plasma inactive renin (major form 56,000 daltons) was consistently larger than renal inactive renin (50,000 daltons).
- Both forms are glycoproteins, suggesting potential differences in carbohydrate composition.
- Inhibition by antirenin antibodies indicates similar primary structures.
Conclusions:
- Plasma and renal inactive renins are structurally similar, likely differing in carbohydrate content.
- The observed molecular size difference is attributed to variations in glycosylation patterns.