Roque-Barreira M C, Praz F, Halbwachs-Mecarelli L, Greene L J, Campos-Neto A
Braz J Med Biol Res. 1986;19(2):149-57.
We describe the use of IgA-Sepharose 4B affinity chromatography to purify the lectin jacalin from saline extracts of Artocarpus integrifolia L. seeds. Elution with 0.8 M D-galactose provides 10-15 mg lectin/50 mg seed protein. Jacalin behaved like a single component on immunoelectrophoresis and a single, somewhat diffuse band was obtained by polyacrylamide gel electrophoresis (PAGE) at pH 4.5. A single peak corresponding to an apparent molecular weight of 43 kDa was obtained by gel filtration on Sephadex G-75 (10 mM phosphate buffered saline (PBS), pH 7.4). On SDS-PAGE +/- 2-mercaptoethanol two bands of apparent molecular weights 11.8 and 14.7 kDa were detected. Jacalin behaved like a protein of apparent molecular weight of 13-14 kDa on Sephadex G-50 eluted with PBS containing 0.2% SDS. These data indicate that the jacalin molecule consists of 3-4 non-identical polypeptide subunits not connected by disulfide bridges. The amino acid composition of IgA affinity-purified jacalin (mol/405 mol amino acids) is Lys (24), His (5), Arg (4), Trp (6), Asx (36), Thr (35), Ser (48), Glx (31), Pro (18), Gly (53), Ala (13), Val (25), Met (3), Ile (23), Leu (25), Tyr (30), Phe (26), which corresponds to a molecular weight of 44.163 kDa.
我们描述了使用IgA-琼脂糖4B亲和色谱法从波罗蜜种子的盐提取物中纯化凝集素jacalin的方法。用0.8 M D-半乳糖洗脱可得到10 - 15 mg凝集素/50 mg种子蛋白。在免疫电泳中，jacalin表现为单一成分，在pH 4.5条件下通过聚丙烯酰胺凝胶电泳（PAGE）得到一条单一的、有点弥散的条带。在Sephadex G-75（10 mM磷酸盐缓冲盐水（PBS），pH 7.4）上进行凝胶过滤，得到一个对应表观分子量为43 kDa的单峰。在SDS-PAGE +/- 2-巯基乙醇条件下，检测到两条表观分子量分别为11.8 kDa和14.7 kDa的条带。在用含0.2% SDS的PBS洗脱的Sephadex G-50上，jacalin表现为表观分子量为13 - 14 kDa的蛋白质。这些数据表明，jacalin分子由3 - 4个不相同的多肽亚基组成，它们之间没有通过二硫键连接。IgA亲和纯化的jacalin的氨基酸组成（每405摩尔氨基酸中的摩尔数）为：赖氨酸（24）、组氨酸（5）、精氨酸（4）、色氨酸（6）、天冬氨酸和天冬酰胺（36）、苏氨酸（35）、丝氨酸（48）、谷氨酸和谷氨酰胺（31）、脯氨酸（18）、甘氨酸（53）、丙氨酸（13）、缬氨酸（25）、甲硫氨酸（3）、异亮氨酸（23）、亮氨酸（25）、酪氨酸（30）、苯丙氨酸（26），这对应于分子量为44.163 kDa。
