ELECTROPHORETIC CHARACTERIZATION OF POSTTRANSLATIONAL MODIFICATIONS OF HUMAN PAROTID SALIVARY ALPHA-AMYLASE
ELECTROPHORETIC CHARACTERIZATION OF POSTTRANSLATIONAL MODIFICATIONS OF HUMAN PAROTID SALIVARY ALPHA-AMYLASE
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DOI：
10.1002/elps.1150120114
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发表时间：
1991-01-01
期刊：
影响因子：
2.9
通讯作者：
PRONK, JC
中科院分区：
文献类型：
--
作者：
BANK, RA;HETTEMA, EH;PRONK, JC
人唾液α-淀粉酶在聚丙烯酰胺凝胶电泳上显示多条带。 在新鲜唾液中，由于翻译后修饰，观察到5-6种同工酶的模式。 按阳极活动性增加的顺序，将同工酶指定为1-6。 由于开发了快速和灵敏的电泳系统，其分辨率明显高于先前报道的，我们得出结论，先前提出的模型（Karn等人，生物化学遗传学1973年，10，341-350）是不足以解释各种乐队的起源。 我们提出了一个替代模型，适合我们的新的和以前的观察。 根据这个模型，带2是主要的基因产物，带1是它的糖基化对应物每个分子上只有一个中性寡糖。 条带3通过transalidase催化将唾液酸并入双触角链而源自条带1。 条带4和6分别来自条带2和4的脱酰胺作用;条带5是淀粉酶与酸性寡糖的脱酰胺作用产物（条带3）。 条带3中只有一小部分由条带1的脱酰胺产物组成。 肽Asn-Gly-Ser（残基427-429）是最可能的糖基化候选物;文献数据表明，脱酰胺发生在Glu-Asn-Gly-Lys-Asp（残基364-368）和Asn-Gly-Asn-Cys（残基474-477）段。 糖基化和脱酰胺化可能在体循环中淀粉酶的清除中起作用。 所描述的电泳系统是确定淀粉酶同工酶在健康和疾病中的分布的有力工具，特别是对于在异位产生的淀粉酶中看到的改变的筛选。
Human salivary alpha-amylase displays multiple bands upon native polyacrylamide gel electrophoresis. In fresh saliva, due to posttranslational modifications, a pattern of 5-6 isozymes is observed. The isozymes are designated 1-6, in the order of increasing anodal mobilty. As a result of the development of a rapid and sensitive electrophoresis system, with markedly higher resolution than previously reported, we concluded that a previously proposed model (Karn et al., Biochem. Genet. 1973, 10, 341-350) is inadequate to explain the origin of the various bands. We propose an alternative model that fits in with our new and previously made observations. According to this model, band 2 is the primary gene product and band 1 is its glycosylated counterpart-with only one neutral oligosaccharide present on each molecule. Band 3 originates from band 1 by the transialidase-catalyzed incorporation of sialic acid into the biantennary chain. Bands 4 and 6 originate from bands 2 and 4, respectively, by deamidation; band 5 is the deamidation product of amylase with an acidic oligosaccharide (band 3). Only a minor part of band 3 consists of the deamidation product of band 1. Peptide Asn-Gly-Ser (residues 427-429) is the most probable candidate for glycosylation; literature data suggests that deamidation occurs in the stretch Glu-Asn-Gly-Lys-Asp (residues 364-368) and Asn-Gly-Asn-Cys (residues 474-477). Both glycosylation and deamidation might play a role in the clearance of amylase from the systemic circulation. The electrophoresis system described is a powerful tool to determine amylase isozyme distributions in health and disease, especially for the screening of alterations seen in ectopically produced amylase.