牛乳黄嘌呤氧化酶与免疫球蛋白的共纯化

Copurification of bovine milk xanthine oxidase and immunoglobulin.

作者信息

Clare D A, Lecce J G

机构信息

Department of Animal Science, North Carolina State University, Raleigh.

出版信息

Arch Biochem Biophys. 1991 Apr;286(1):233-7. doi: 10.1016/0003-9861(91)90034-g.

DOI:10.1016/0003-9861(91)90034-g

PMID:1910286

Abstract

Xanthine oxidase, isolated from bovine milk, exhibited an A280:A450 nm ratio of 5.0. This ratio is reported to be indicative of highly purified enzyme preparations. Serum from a rabbit hyperimmunized against this enzyme fraction exhibited two precipitation lines when incubated with the protein in agarose double diffusion plates. Serum albumin, beta-lactoglobulin, alpha-lactalbumin, lactoferrin, casein, chymosin, and immunoglobulin were tested for reactivity. The second antigen was identified as bovine immunoglobulin. Commercial preparations of xanthine oxidase also contained immunoglobulin as a contaminant. IgG and IgA were present in Sigma (Grade III) fractions and IgM was identified in Boehringer Mannheim preparations. Immunofluorescent studies indicated that xanthine oxidase antiserum reacted with the capillary endothelium of bovine heart. Absorption of this antiserum with bovine IgG abrogated this reaction. These findings may explain apparent discrepancies between reported immunohistological association of xanthine oxidase in heart capillary endothelial cells and the absence of detectable enzymatic activity.

摘要

从牛乳中分离出的黄嘌呤氧化酶，其280nm与450nm吸光度之比为5.0。据报道，该比值表明酶制剂高度纯化。用该酶组分对兔进行超免疫后获得的血清，在琼脂糖双向扩散平板中与该蛋白孵育时出现两条沉淀线。对血清白蛋白、β-乳球蛋白、α-乳白蛋白、乳铁蛋白、酪蛋白、凝乳酶和免疫球蛋白的反应性进行了检测。第二种抗原被鉴定为牛免疫球蛋白。黄嘌呤氧化酶的商业制剂中也含有作为污染物的免疫球蛋白。Sigma（III级）组分中存在IgG和IgA，在Boehringer Mannheim制剂中鉴定出IgM。免疫荧光研究表明，黄嘌呤氧化酶抗血清与牛心脏的毛细血管内皮发生反应。用牛IgG吸收该抗血清可消除此反应。这些发现可能解释了报道的黄嘌呤氧化酶在心脏毛细血管内皮细胞中的免疫组织学关联与未检测到酶活性之间明显的差异。