Abstract
Plasteins were synthesized from a peptic sardine protein hydrolysate by pepsin, ${\alpha}-chymotrypsin$ pretense(from Aspergillus saitoi) and papain under the optimum conditions of previous paper. L -glutamic acid diethylester and L-leucine ethylester also were incorporated into plastein during the plastein reaction by papain. General composition, yield, molecular weight and amino acid composition were measured. The protein, ash and lipid rontent of plasteins were $81.1{\sim}88.2%$, $1.9{\sim}7.6%$ and $0.3{\sim}0.8%$, respectively. The yield of plasteins were pretense plastein 52.3%, papain plastein 44.2%, pepsin plnstein 43.6%, ${\alpha}-chymotrypsin$ plastein 43.2%. Leu -papain plastein 33. 2% and Glu - papain plastein 29.0%. The glutamic acid and leucine content in Glu -papain plastein and Leu -papain plastein were 39.0%, 37.5%, respectively. While the contents in the papain plastein were 14.3%, 7.1%, respectively. The amino acid composition of plasteins were similar to that of peptic sardine protein hydrolysate. The major molecular weight of the peptic hydrolysnte estimated by gelfilteration were 1,800 and 285, and those of plasteins were 26,000 and 9,100 for ${\alpha}-chymotrypsin$, 23,000, 10,000 and 4,300 for pepsin, 18,000 for pretense, 13,000 for papain, 29,000 for Leu -papain plastein and 19,000 for Glu -papain plastein.
Pepsin, ${\alpha}-chymotrypsin$, protease 및 papain을 이용하여 정어리육 단백질의 pepsin가수분해물로 부터 합성한 plastein과 유리 glutamic acid 및 leucine을 도입시킨 plastein의 일반성분, 수율, 아미노산조성 및 분자량을 측정하여 비교 검토한 결과 plastein의 단백질 함량은$82.0{\sim}88.2%$였으며 회분함량은 $2.7{\sim}7.6%$로 glu-papain plastein과 leu-papain plastein의 2.5% 및 1.9%보다 높았고, 지방함량은 $0.3{\sim}0.8%$범위였다. 수율은 protease plastein이 52.3%로 가장 높았고, papan plastein, pepsin plastein 및 ${\alpha}-chymotrypsin$ plastein은 각각 44.2%, 43.6%, 43.2%였으며, leu papain plastein과 glu-papain plastein은 각각 33.2% 및 29.0%였다. plastein종류에 따른 아미노산조성에는 큰 차이는 없었으며, leu-papain plastin과 glu-papain plastein의 leucine 및 glutamlc acid 함량은 각각 37.5% 및 39.3%였으나 대조구인 papain plastein에서는 이들의 함량이 7.1%, 14.4%에 불과하였다. 겔여과에 의한 가수분해물의 분자량은 1,800 및 285인 것이 주종을 이루었으나 이외에 분자량 3,600 및 830인 획분도 존재하였다. plasteln의 분자량은 ${\alpha}-chymotrypsin$ plastein이 26,000 및 9,100였으며 pepsin plastein은 23,000이 주증을 이루었고, 10,000 및 4,300도 존재하였고, protease plastein의 분자량은 18,000였다. leu-papain plastein과 glu-papain plastein은 각각 29,000 및 19,000 였으나 papain plastein 은 13,000로 가장 낮았다.