腹足纲Helix pomatia βC-血清蛋白的功能单位e中碳水化合物的定位和糖基化位置的鉴定

对腹足纲软体动物罗曼蜗牛Helix pomatia的氧运输蛋白(βc-血清蛋白)的功能单位e中的碳水化合物进行了研究。以该βc-血清蛋白为载体，通过限制性胰蛋白酶水解，产生片段a-c，ef，以及功能单位d，g，和h。以片段ef降解后的产物为研究对象，通过亲合色谱的分离纯化，得到功能单位e的一个馏分e2。该馏分经还原、吡啶乙基化和胰蛋白酶水解后，通过柱色谱的分离纯化，得到一个含有糖肽的成分。对该糖肽中糖组分和肽序列的分析，最终确定了功能单位e的两个糖基化位置：Asn-lll和Asn-387。通过与功能单位d和g的糖基化位置的比较得出结论：Asn-387为一恒定的糖基化位置。

Location of The Carbohydrate and Identification of The Glycosylation Sites in Functional Unit e of βc-haemocyanin of The Gastropod Helix Pomatia

The carbohydrate in functional unit e of βC-haemocyanin of the gastropod Helix pomatia was studied. The limited trypsinolysis on tenth molecules of βC-haemocyanin of Helix pomatia at pH = 8. 2 yielded the fragments αc, e f, and the functional units d, g, and h (present as dimers h2). The mixture of functional units e and f after limited fragmentation of fragment ef on storage, were further fractionated with an affinity chromatography in the presence of α-methylglucoside, yielded functional unit e2. Further separation of trypsinolysis of pyridylethylated functional unit e2 yielded a fraction I (contain glycopeptides). The analysis of carbohydrate content and the N-terminal sequence allowed the location of the carbohydrate and the identification of the glycosylation sites in functional unit e: site A at Asn-111 and site B at Asn-387. From a comparison with the glycosylation sites of Hp d and Hp g, it follows that the site B is a conserved one.