Biochemical properties of the renin binding substance of rat kidney

Renin extracted from isolated renin granules of the rat is a low molecular weight form (40,000 daltons). The renin binding substance which is capable of binding with the low molecular weight renin to form a high molecular weight renin (60,000 daltons) under sulfhydryl oxidation was found to be contained in the crude extract of rat renal cortex. This substance is presumably a protein with molecular weight of over 47,000 daltons by gel filtration. The most striking event was that rat renin binding substance was bound with dog renin and vice versa.