Amino‐Acid Sequences of Red‐Deer and Roe‐Deer Pancreatic Ribonucleases

Pancreatic ribonucleases from red deer ( Cervus elaphus ) and roe deer ( Capreolus capreoluus ) have been isolated and the amino acid sequences of both enzymes have been determined. Red deer ribonuclease exists only in a carbohydrate‐free form. Roe deer ribonuclease has been isolated both in a carbohydrate‐free form and in a glycosidated form. The difference in glycosidation between the enzymes from both deer species could be explained by the substitution of an asparagine at position 34 (the carbohydrate attachment site in the glycosidated form of roe deer ribonuclease) by lysine in the red deer enzyme. Both enzymes also differ at position 35 (methionine in red deer, leucine in roe deer). Roe deer ribonuclease exhibits heterogeneity in having both alanine and isoleucine at position 64. All other amino acid positions are occupied by identical residues in both enzymes. Red deer ribonuclease differs at 19 positions from bovine ribonuclease. A value of 1% substitution per 3.10 6 year has been calculated for the rate of molecular evolution of mammalian pancreatic ribonucleases from 7 amino acid sequences determined to date.