Specificity and Localization of Renin-Binding Protein(s)

There is almost no doubt about the presence of renin-binding protein(s) in mammalian kidneys. However, renin-binding protein has never been purified and fully characterized. Its physiological role is unclear. We found that hog renal renin-binding protein could bind homologous and non-homologous renin but could not bind human renal renin. Renin-binding protein was only detected in the kidney and pituitary in which renin is found in relatively high concentration. The renal binding protein had no interaction with renal acid proteases nor with extrarenal renins obtained from the pituitary and submaxillary glands, indicating that the binding is specific for renal renin.