Morita T, Jackson C M
J Biol Chem. 1986 Mar 25;261(9):4008-14.
Bovine Factor X is isolated in two chromatographically separable forms, Factor X1 and Factor X2. Whereas only a single form of Factor Xa, the active protease, exists, the activation peptides also exist as two chromatographically distinct species. These peptides have been shown to differ at a tyrosyl residue by ultraviolet spectrophotometry, and in their composition after alkaline hydrolysis. On the basis of the spectral properties, and elution position of the modified tyrosine on Dowex 1 columns and on an amino acid analyzer, it has been concluded that Factor X2 contains a tyrosyl-O-SO4 residue at position 18 in the activation peptide whereas Factor X1 contains only tyrosine. Alternative explanations such as differences in carbohydrate composition, differences in phosphate content, or differences in the number of gamma-carboxyglutamic acid residues were demonstrated to be unrelated to the difference in chromatographic behavior between bovine Factors X1 and X2.
牛凝血因子X以两种可通过色谱分离的形式被分离出来，即因子X1和因子X2。虽然活性蛋白酶因子Xa只有单一形式存在，但激活肽也以两种色谱上不同的种类存在。通过紫外分光光度法已表明这些肽在一个酪氨酰残基处存在差异，并且在碱性水解后的组成也不同。基于光谱特性、修饰酪氨酸在Dowex 1柱上的洗脱位置以及在氨基酸分析仪上的洗脱位置，已得出结论：因子X2在激活肽的第18位含有一个酪氨酰-O-硫酸酯残基，而因子X1只含有酪氨酸。诸如碳水化合物组成差异、磷酸盐含量差异或γ-羧基谷氨酸残基数量差异等其他解释已被证明与牛因子X1和X2之间色谱行为的差异无关。
