Abstract
Changes of silk protein compositions of average molecular weight (Mw) and free amino acid composition to different solubility conditions were studied by SDS-polyacrylamide electropholesis, gel permeation chromatography (GPC), and free amino acid analysis method. We can not detected average molecular weight distribution of different hydrochloric acid (HCl) conditions as SDS-polyacrylamide method, but as using GPC method, molecular weight distribution of 2N-HCl, 1N-HCl and 0.5N-HCl (3 hrs at $110^{\circ}C$ treated) are confirmed Mw 800, 1,500 and 3,700, respectively. The average molecular weight of calcium chroride and calcium chloride-enzyme treated samples are shown Mw 46,800 and 12,500, respectively. The degree of hydrolysis and the composition of the free amino acid in the fibroin hydrolysates effected significantly composition of free amino acids of the fibroin powder. The increase of the degree of hydrolysis and ratio of free amino acids and oligopeptides were found to be directly related to the concentration of hydrochloric acid and treatment of enzyme, resulting in the increase of water solubility.
몇 가지 용해조건에 따른 견 단백절의 조성 변화를 SDS-polyacrylamide 전기영동법, Gel Permeation Chromatography(GPC)법 및 유리아미노산 분석을 통하여 연구하였다. 분자량의 변화에 있어 염산을 이용한 가수분해법의 경우, SDS-PAGE 방법으로는 분자량의 분포를 확인할 수 없었다. 그러나 2N-HCl, 1N-HCl, 0.5N-HCl (3시간 $110^{\circ}C$)와 중성염($CaCl_2$) 및 중성염-효소로 가수분해시킨 견 피브로인 단백질의 평균 분자량 분포는 GPC법에 의하여 각각 Mw 800, 1,500, 3,700과 46,800, 12,500으로 확인되었다. 또한 용해 조건에 의한 유리아미노산 함량은 염산의 농도가 높을수록, 효소를 사용함으로써 유리아미노산의 조성이 증가함을 알 수 있었다.
