Kitamura T, Yoshioka K, Ehara M, Akedo H
Gastroenterology. 1977 Jul;73(1):46-51.
Characteristics of a macroamylase that was considered not to be formed by the binding of normal amylase to immunoglobulins were studied. The macroamylase was reversibly dissociated into apparently normal amylase by treating the macroamylasemic serum with guanidine hydrochloride. Concanavalin A precipitated a large portion of the macroamylase. When the macroamylase was purified by affinity chromatography using an insoluble starch polymer at neutral pH, a considerable dissociation of the enzyme into apparently normal amylase was observed with the purified preparation. Such dissociation of the macroamylase was demonstrated by briefly incubating the patient's serum with a low-molecular weight starch, a substrate of the enzyme. This dissociated enzyme showed upon electrophoresis essentially the same isozymic pattern as that of normal serum amylase. When the patient's serum was incubated with the low molecular weight starch for a prolonged period to hydrolyze the starch completely and was dialyzed, reconstitution of macroamylase resulted. The amylase-binding substance(s) that is supposed to be involved in the formation of macroamylase was found to release when the enzyme was adsorbed on the insoluble starch polymer at 0 degrees C. The present results strongly suggest that the amylase-binding substance(s), probably polysaccharide(s) or glycoprotein(s), binds to the substrate-binding site of normal amylase to form a macroamylase complex.
对一种被认为不是由正常淀粉酶与免疫球蛋白结合形成的巨淀粉酶的特性进行了研究。通过用盐酸胍处理巨淀粉酶血症血清，巨淀粉酶可逆地解离为明显正常的淀粉酶。伴刀豆球蛋白A沉淀了大部分巨淀粉酶。当在中性pH下使用不溶性淀粉聚合物通过亲和色谱法纯化巨淀粉酶时，在纯化制剂中观察到该酶大量解离为明显正常的淀粉酶。通过将患者血清与低分子量淀粉（该酶的一种底物）短暂孵育，证明了巨淀粉酶的这种解离。这种解离的酶在电泳时显示出与正常血清淀粉酶基本相同的同工酶模式。当将患者血清与低分子量淀粉长时间孵育以完全水解淀粉并进行透析时，会导致巨淀粉酶的重新形成。当酶在0℃吸附在不溶性淀粉聚合物上时，发现 supposed to be involved in the formation of macroamylase的淀粉酶结合物质(s)会释放。目前的结果有力地表明，淀粉酶结合物质(s)，可能是多糖或糖蛋白，与正常淀粉酶的底物结合位点结合形成巨淀粉酶复合物。
