Van den Berg A, Van den Hende-Timmer L, Hofsteenge J, Gaastra W, Beintema J J
Eur J Biochem. 1977 May 2;75(1):91-100. doi: 10.1111/j.1432-1033.1977.tb11507.x.
Two ribonucleases were isolated from guinea-pig pancreas by extraction with 0.125 M sulfuric acid, precipitation with acetone and chromatography on carboxymethyl-cellulose. The amino acid sequences were determined from tryptic digests of the aminoethylated proteins. The tryptic peptides were positioned in the sequence by homology with other pancreatic ribonucleases. Both ribonucleases not only differ in the presence (ribonuclease B) or absence of carbohydrate (ribonuclease A), but also at 31 positions of the amino acid sequence. In guinea-pig ribonuclease B a leucine/proline heterogeneity was found at position 64. The carbohydrate in guinea-pig ribonuclease B is attached to asparagine residues at positions 21 and 34. The carbohydrate-free guinea-pig ribonuclease A possesses a recognition site for sugar attachment in the sequence Asn-Val-Ser (62-64).
通过用0.125M硫酸提取、丙酮沉淀以及羧甲基纤维素柱层析，从豚鼠胰腺中分离出了两种核糖核酸酶。从氨乙基化蛋白质的胰蛋白酶消化产物中测定了氨基酸序列。通过与其他胰腺核糖核酸酶的同源性，将胰蛋白酶肽定位在序列中。这两种核糖核酸酶不仅在是否存在碳水化合物（核糖核酸酶B有碳水化合物，核糖核酸酶A没有）上不同，而且在氨基酸序列的31个位置上也不同。在豚鼠核糖核酸酶B中，第64位发现了亮氨酸/脯氨酸异质性。豚鼠核糖核酸酶B中的碳水化合物连接在第21位和第34位的天冬酰胺残基上。无碳水化合物的豚鼠核糖核酸酶A在序列Asn-Val-Ser（62 - 64）中具有一个糖附着识别位点。
