Structure of Mouse Submaxillary Gland Renin

Abstract
To determine the structural basis for the highly specific action of renin, structural features of the active site and the complete amino acid sequence of mouse submaxillary gland renin were determined. A rapid method was developed for a large scale purification of renin from mouse submaxillary gland. The active site of renin was shown to consist of 2 aspartyl residues, 2 tyrosyl residues and one arginyl residue, the structures analogous to the active site of pepsin and other acid proteases. Renin was found to consist of one heavy chain (Mr = 31,036) and one light chain (Mr = 5,458) connected by a disulfide bridge. Amino acid sequences of these chains were determined using overlapping peptides generated by cleavage with cyanogen bromide, trypsin, Staphylococcus aureus protease and Lysobacter enzymogenes endoproteinase Lys-C. Sequences involving 2 catalytically essential aspartyl residues 32 and 215, characteristic to acid proteases, were found identical with pepsin, penicillopepsin and chymosin. The sequence of L-chain was homologous with carboxyl terminal region of porcine pepsin in 46% of amino acid residues. H-chain showed 41% homology with 284 residues on the amino-terminal side of the porcine pepsin molecule. Residues identical in renin and acid proteases are distributed throughout the length of the molecules, suggesting a similarity in their overall structure.