Townsend R R, Heller D N, Fenselau C C, Lee Y C
Biochemistry. 1984 Dec 18;23(26):6389-92. doi: 10.1021/bi00321a016.
Sialylated biantennary glycopeptides from human fibrinogen were analyzed with fast atom bombardment mass spectrometry. The mass spectrometric conditions used in the positive mode showed predominantly molecular ions with no fragment ions due to the loss of sialic acid. Standard mixtures of glycopeptides with zero, one, and two sialic acid residues revealed a linear relationship between ion abundance and molar fraction. The desorption efficiency varied according to the number of sialic acid residues in these biantennary glycopeptides. The relative abundance of different molecular ion species differing only in amino acid content was in agreement with chemical analysis. Sensitivity, precision, and requirements for sample preparation were assessed. Both assignment of molecular weights and quantification of individual glycopeptide species from human fibrinogen were obtained. The glycopeptides from human fibrinogen were found to consist of a mixture of equal amounts of monosialylated and disialylated species with no asialoglycopeptides.
采用快原子轰击质谱法分析了人纤维蛋白原的唾液酸化双天线糖肽。正模式下使用的质谱条件显示，主要为分子离子，未出现因唾液酸丢失而产生的碎片离子。含有零个、一个和两个唾液酸残基的糖肽标准混合物显示出离子丰度与摩尔分数之间的线性关系。这些双天线糖肽的解吸效率根据唾液酸残基的数量而变化。仅在氨基酸含量上有所不同的不同分子离子种类的相对丰度与化学分析结果一致。评估了灵敏度、精密度和样品制备要求。获得了人纤维蛋白原的分子量分配和各个糖肽种类的定量结果。发现人纤维蛋白原的糖肽由等量的单唾液酸化和双唾液酸化种类的混合物组成，不存在去唾液酸糖肽。
