【摘要】 本文进一步报道了在我国传统的"酸浆法"生产淀粉的过程中,乳酸链球菌(Streptococcuslactis)菌体上的何种物质使淀粉粒凝集。实验表明,能使蛋白质变性的各种物理因素及化学因素如加热、紫外线照射、超声波以及用苯酚、三氯乙酸、甲醛、来苏尔等,都能使乳酸链球菌凝集淀粉粒的作用完全丧失;用糜蛋白酶处理菌体后,菌体凝集淀粉粒的作用也完全丧失,而用被Kunitz 抑制剂抑制了的糜蛋白酶或用纤维素酶、果胶酶、脂肪酶、胃蛋白酶、胰蛋白酶、木瓜蛋白酶、溶菌酶处理菌体,则仍然保留其凝集淀粉的能力。上述实验暗示,对淀粉粒的凝集起作用的是菌体表面上的某种蛋白质类物质,很可能是某种凝集素(lectins)。本文还报道了菌体、淀粉粒和阳离子三者之间量的关系,它们之间量的正相关表明,在凝集作用中,三者可能是以某种方式结合在一起的。结合的性质还待进一步研究。更多还原

【Abstract】 In a previous paper,we have shownthat in the Chinese traditional "sourliquid" method of starch production,it isneither the acidity,nor any of the fer-mentation products,but the microorgan-ism itself,that causes the precipitation ofstarch grains.The microorganism con-tained in the liquid agglutinates starch,thereby making the dispersed starchgrains to aggregate into big masses.Theagglutinating action between the micro-organism and the starch grains requirescertain conditions:an optimal pH,a pro-per temperature and the presence of cer-tain cations.Monovalent cations and cer-tain divalent cations such as Sr²⁺ andBa²⁺ have no effect,while Ca²⁺ has a weakeffect.Among the di- tri- and tetravalentcations tested,the agglutinating effect in-creases with the valency.The responsiblemicroorganism has been isolated andcharacterized as a variety of Streptococcuslactis.In the present paper,experimentswere designed to study the effect ofvarious physical and chemical factors,together with a series of enzyme prepara-tions,on the agglutination between thebacteria and the starch grains.All treat-meats which are known to denature pro-teins led to the loss of agglutinatingability of the bacteria.These included;heating,treatment with phenol,trichlo-roacetic acid,formaldehyde and lysol,ultraviolet radiation,ultrasonic waves,etc.Among the various enzymes tested,cellulase,pectinase,lipase,pepsin,trypsin,papain,lysozyme did not destroy theagglutinating ability of the bacteria,whereas chymotrypsin completely abolish-ed it.Chymotrypsin which had been in-hibited by kunitz inhibitor no longerdestroyed the agglutinating action of thebacteria.According to the above experiments,it is believed that some special proteins,perhaps lectins,on the bacterial surfaceare responsible for the agglutinatingaction between the bacteria and the starchgrains.In this paper,the quantitative rela-tions among the bacteria,the starch grainsand the cations were also studied.The posi-tive quantitative relationship among themseems to suggest that in the agglutinationreaction,these three are in some fashionbound together.The nature of the bind-ing sites remains to be investigated.更多还原