Yoshikazu Sahashi

The Syntheses of Peptides by the Phthaloyl Method

We modified the phthaloyl method for the syntheses of peptides. In the presence of sodium acetate or potassium acetate, phthalimidoacyl chlorides readily reacted with variousamino acids in glacial acetic acid to give corresponding phthaloyl peptides. By this method we synih-esized following phthaloyl-derivatives; phthaloy l-glycylanilide, -glycylglycine, -glycyl-DL-ala nine, -glycyl-L-leucine, -glycyl-DL-phenylalanine, -glycyl-L-phenylalanine, -glycyl-DL-valine, glycylglycylglycine, -DL-alanyl-DL-alanine, -DL-alanyl-DL-phenylalanine, -DL-phenylalanylglycine, -DL-phenylalanyl-DL-alanine and -DL-phenylalanyl-DL-phenylalanine. By the hydrazinolysis of these phthaloyl peptides we readily obtained corresponding peptides in moderate yield.

On the Micro-determination of Sulfhydryl Group in Denatured Proteins

In 1941 it was reported by P. ZIMA that the sulfhdryl group in cysteine or glutathione molecules may be calculated by treating with aneurin disulfide and then estimating the micro-amount (0.2_??_0.5γ) of aneurin in the obtained solution with the thiochrome method. Recently the present authors have carried out a few micro analytical experiments of SH group determination in denatured proteins by this O. ZIMAs aneurin disulflde method. The results are briefly summarized as follows: 1) Studies on the estimation of the SH group in egg-albumin denatured by urea were successfully completed. 2) But, on the other hand, no accruated results were obtained in the experiments with egg-albumin denatured by guanidine hydrochloride.

On the Effect of Linoleic Acid and Yeast upon the Growth of Rats on High Fat Diet

Albino rats failed to secure satisfactory growth on diets containing a high percentage of any of the fats used except butter. The addition of yeast to the diet did not improve the growth of the animals. With the supple-mentary feeding of linoleic acid in addition to yeast the animals attained nearly the normal rate of growth, demonstrating anew the importance of linoleic acid as a dietary element.