Ser + Gln)4.9o. The [Ser6,Orn'°]-S-peptide gave, after recombination in a 1:1 molar ratio with S-protein, a 40% active partially synthetic ribonuclease.Lysylglutamylthreonylalanylalanylprolyllysylphenylalanylglutamylornithylglutaminylhistidylmethionylaspartylserylserylthreonylserylalanylalanine (3G, Pro6 1-20). The condensation of 3D, Pro6 1-12 (0.335 g, 0.174 mmol), with 3E, 13-2013 (0.306 g, 0.348 mmol, as monoacetate, trihydrate), by the azide procedure was carried out as described above for 3G, Ser51-20, and gave the partially protected [Pro5,Orn10]-S-peptide (3F, Ser6 1-20; 0.264 g, 57%). Treatment of the crude product with anhydrous TFA (2.5 ml), purification on Amberlite CG 50 and on Sephadex G-25, followed by lyophilization gave the pure [Pro6,Ornn]-S-peptide (3G, Pro6 1-20; 0.053 g, 25%), [a]23D-97.5 ± 10 (c 0.117, water); single ninhydrin-and Pauly-positive component on paper electrophoresis at pH 1.9, 3.5, 6.4, and 9.5; amino acid ratios in acid hydrolysate: Lysz. ooGlu2. gsThn. 95Ala3.soOrni. O0Phei. 05HÍS1. osProo. 95-Met0.97Asp1.00Ser2.95; amino acid ratios in AP-M digest: Lysi.97-Glui.95Thr2.ooAla3.9oOrn0.95Phe0.97Hiso.97Proo.97Meti.ooAspo.95(Ser + Gln)4.o5. The [Pro6,Orn10]-S-peptide gave, after recombination in a 1:1 molar ratio with S-protein, a 15% active partially synthetic ribonuclease.
