以成熟的莱阳茌梨果实为试材，应用同源克隆和 RACE 方法从茌梨果肉中克隆到内切－β－1，4－葡聚糖酶基因的一个同源基因 cDNA 的全长序列，命名为 PbEG，其碱基长度为1971 bp，PbEG 的开放阅读框编码493个氨基酸，相对分子量为54．5961 kDa，等电点为9．14；PbEG 编码的蛋白属于糖基水解酶第9家族，不含有跨膜区域但在 N－端含有一段信号肽。其编码氨基酸同源性分析表明，茌梨 PbEG 基因与蓖麻 EG 基因同源性较高，达到84％，其次是豌豆和葡萄。% One full-length cDNA sequence of homologous gene endo -β-1,4-glucanas from Pyrus bretschneideri Rehd.Cv.Chili pear was cloned by polymerase chain reaction (PCR) and RACE method,which was named as PbEG.The PbEG was 1 971 bp and the open reading frame encoded 493 amino acids,while the estimated molecular weight and isoelectric point of the putative protein were 54.596 1 kDa and 9.14.The protein encoded by PbEG be-longed to Glycosyl-hydrolases-family-9.There was no membrane-spanning domain in the protein but a signal peptide in the N-terminus.And the deduced amino acids homology analysis indicated that PbEG has a high homology with RcEG(84%).
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