Kit Y Y, Semenov D V, Kuligina E V, Richter V A
Novosibirsk Institute of Bioorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia.
Biochemistry (Mosc). 2000 Feb;65(2):237-43.
The influence of nucleic acids (DNA, tRNA), synthetic oligonucleotides, and polysaccharides (lipopolysaccharides from Escherichia coli, heparin) on protein kinase and lipid kinase activities of preparations of human secretory immunoglobulin A (sIgA) has been studied. The preparations of sIgA were isolated from human milk by chromatography on the column with Protein A-Sepharose and DEAE-sorbent (sIgA1), by affinity chromatography of sIgA1 on DNA-cellulose (sIgA2), and by gel-filtration of sIgA1 in buffer containing 5% dioxane (sIgA3). Two 32P-labeled products with high and low electrophoretic mobility in polyacrylamide gel containing SDS were found after incubation of sIgA1 and sIgA2 with [gamma-32P]ATP. The product with low electrophoretic mobility was degraded in 10% trichloroacetic acid giving a radioactive background in lanes of the polyacrylamide gel. 32P-Labeled phospholipids were found among the phosphorylation products. Soluble and immobilized DNA increase lipid kinase activity of preparations of sIgA. In this case the secretory component and H-chains of sIgA were degraded. Fractions possessing lipid kinase activity were precipitated in the presence of heparin (1 mg/ml), and lipid kinase activity was separated from sIgA by gel-filtration in buffer containing 5% dioxane. 32P-Labeled products were formed in the presence of [gamma-32P]ATP as well as [32P]ortho-phosphoric acid. The influence of heparin and synthetic deoxy- and ribooligonucleotides on casein kinase activity of sIgA3 was studied. It was observed that deoxyribooligonucleotides in micromolar concentrations increased the rate of casein phosphorylation in the presence of sIgA3 and [gamma-32P]ATP. It has been proposed that catalytically active sIgA have an affinity to DNA (anti-DNA sIgA) and can be present in human milk as a part of lipoprotein complexes.
研究了核酸（DNA、tRNA）、合成寡核苷酸和多糖（大肠杆菌脂多糖、肝素）对人分泌型免疫球蛋白A（sIgA）制剂的蛋白激酶和脂质激酶活性的影响。通过在蛋白A-琼脂糖和DEAE吸附剂柱上进行色谱分离（sIgA1）、sIgA1在DNA-纤维素上进行亲和色谱分离（sIgA2）以及在含5%二氧六环的缓冲液中对sIgA1进行凝胶过滤（sIgA3），从人乳中分离出sIgA制剂。将sIgA1和sIgA2与[γ-32P]ATP孵育后，在含SDS的聚丙烯酰胺凝胶中发现了两种具有高和低电泳迁移率的32P标记产物。低电泳迁移率的产物在10%三氯乙酸中降解，在聚丙烯酰胺凝胶泳道中产生放射性背景。在磷酸化产物中发现了32P标记的磷脂。可溶性和固定化DNA增加了sIgA制剂的脂质激酶活性。在这种情况下，sIgA的分泌成分和重链被降解。具有脂质激酶活性的组分在肝素（1mg/ml）存在下沉淀，并且通过在含5%二氧六环的缓冲液中进行凝胶过滤将脂质激酶活性与sIgA分离。在[γ-32P]ATP以及[32P]正磷酸存在下形成了32P标记产物。研究了肝素和合成脱氧及核糖寡核苷酸对sIgA3酪蛋白激酶活性的影响。观察到微摩尔浓度的脱氧核糖寡核苷酸在sIgA3和[γ-32P]ATP存在下增加了酪蛋白磷酸化的速率。有人提出，具有催化活性的sIgA对DNA有亲和力（抗DNA sIgA），并且可以作为脂蛋白复合物的一部分存在于人乳中。
