Sugahara T, Nakajima H, Shirahata S, Murakami H
Graduate School of Genetic Resources Technology Kyushu University, Fukuoka, Japan.
Cytotechnology. 1992;10(2):137-46. doi: 10.1007/BF00570890.
Two immunoglobulin production stimulating factors (IPSF) have been found in human Burkitt's lymphoma Namalwa cells. One IPSF named IPSF-II alpha was purified and identified as glyceraldehyde-3-phosphate dehydrogenase as previously reported. We report here purification, identification and characterization of IPSF-II beta. IPSF-II beta was purified by the serial use of ammonium sulfate fractionation, hydrophobic interaction column chromatography, anion-exchange column chromatography and gel filtration. The IPSF-II beta was estimated as a 46 KD monomeric polypeptide by gel filtration and SDS-PAGE. Partial amino acid sequence of the 46 KD protein was analyzed for 26 amino acid residues. The sequence very closely coincided with enolase (EC 4.2.1.11) derived from various origins and, it was completely homologous with that of human enolase alpha-chain. Rabbit muscle enolase stimulated IgM production of hybridoma lines, and IPSF-II beta had the enzymic activity. These results suggested that IPSF-II beta was alpha-enolase or its isozyme. IPSF activities of IPSF-II beta was stable in alkaline conditions whereas the enzymic activity was rapidly lost in alkaline conditions. Though IPSF-II beta stimulated IgM production of both human-human and mouse-mouse hybridoma lines in serum-free condition, it partially suppressed IgE production of mouse-mouse hybridoma lines.
在人伯基特淋巴瘤Namalwa细胞中发现了两种免疫球蛋白产生刺激因子（IPSF）。如先前报道，一种名为IPSF-IIα的IPSF已被纯化并鉴定为甘油醛-3-磷酸脱氢酶。我们在此报告IPSF-IIβ的纯化、鉴定和特性。通过依次使用硫酸铵分级分离、疏水相互作用柱色谱、阴离子交换柱色谱和凝胶过滤对IPSF-IIβ进行纯化。通过凝胶过滤和SDS-PAGE估计IPSF-IIβ为46 KD的单体多肽。对46 KD蛋白的部分氨基酸序列分析了26个氨基酸残基。该序列与源自各种来源的烯醇化酶（EC 4.2.1.11）非常吻合，并且与人烯醇化酶α链完全同源。兔肌肉烯醇化酶刺激杂交瘤细胞系产生IgM，且IPSF-IIβ具有酶活性。这些结果表明IPSF-IIβ是α-烯醇化酶或其同工酶。IPSF-IIβ的IPSF活性在碱性条件下稳定，而酶活性在碱性条件下迅速丧失。尽管IPSF-IIβ在无血清条件下刺激人-人及小鼠-小鼠杂交瘤细胞系产生IgM，但它部分抑制小鼠-小鼠杂交瘤细胞系产生IgE。
