Hjorth J P, Lusis A J, Nielsen J T
Biochem Genet. 1980 Apr;18(3-4):281-302. doi: 10.1007/BF00484242.
Salivary and pancreatic amylases from the mouse show both structural and quantitative genetic variation encoded within a gene complex on chromosome 3. Two fundamental questions prompted by this variation are whether salivary and pancreatic amylases are derived from different structural genes and whether multiple structural genes are causing the quantitative variation observed in each of the two amylases. These questions were approached by comparing the amylase protein from 12 congenic lines carrying amylase gene complexes derived from different origins. The amylases were purified by affinity chromatography employing the inhibitor cyclohepta-amylose and characterized in terms of amino acid composition, specific activity, molecular weight, and heat stability. They were analyzed by native electrophoresis in polyacrylamide gels and by peptide mapping employing both cyanogen bromide cleavage and restricted proteolysis in the presence of dodecylsulfate. By these techniques, many differences in the structure of pancreatic amylase that were not reflected in the salivary amylase were found among mouse strains. Likewise, a distinct salivary amylase variant was found. These results suggest that independent structural genes exist for the two amylases. Furthermore, by all criteria used, pancreatic amylase from single strains exhibits molecular heterogeneity, whereas heterogeneity was never found for salivary amylase. We conclude that at least four structural genes code for pancreatic amylase while only a single gene, different from any of the pancreatic genes, codes for salivary amylase.
小鼠的唾液淀粉酶和胰腺淀粉酶在结构和数量上均表现出遗传变异，这些变异由位于3号染色体上的一个基因复合体编码。这种变异引发了两个基本问题：唾液淀粉酶和胰腺淀粉酶是否源自不同的结构基因，以及多个结构基因是否导致了在这两种淀粉酶中观察到的数量变异。通过比较来自12个携带源自不同来源的淀粉酶基因复合体的同类系的淀粉酶蛋白，来探讨这些问题。使用抑制剂环庚直链淀粉通过亲和层析法纯化淀粉酶，并从氨基酸组成、比活性、分子量和热稳定性方面对其进行表征。通过聚丙烯酰胺凝胶中的天然电泳以及在十二烷基硫酸盐存在下使用溴化氰裂解和限制性蛋白水解的肽图谱分析对它们进行分析。通过这些技术，在小鼠品系中发现了胰腺淀粉酶结构上的许多差异，而这些差异在唾液淀粉酶中并未体现。同样，还发现了一种独特的唾液淀粉酶变体。这些结果表明，这两种淀粉酶存在独立的结构基因。此外，根据所使用的所有标准，单个品系的胰腺淀粉酶表现出分子异质性，而唾液淀粉酶从未发现异质性。我们得出结论，至少有四个结构基因编码胰腺淀粉酶，而只有一个与任何胰腺基因都不同的基因编码唾液淀粉酶。
