Thermal instability of the trimeric structure of the N-terminal propeptide of human procollagen type I in relation to assay technology.
Thermal instability of the trimeric structure of the N-terminal propeptide of human procollagen type I in relation to assay technology.
复制标题
人 I 型原胶原 N 端前肽三聚体结构的热不稳定性与检测技术的关系。
作者：
J. Brandt;T. Krogh;C. Jensen;Jette K. Frederiksen;B. Teisner
Ⅰ型前胶原（PINP）N端前肽经分子筛层析后出现两个峰。在37 ℃孵育期间，高分子量形式转化为低分子量形式，而低分子量形式保持不变。当使用ELISA测量时，羊水和血清中的PINP浓度在37 ℃孵育期间保持不变;然而，当使用RIA测量时，浓度降低了89-93%。由于不同的尺寸分布和RIA无法测量低分子量形式，这些液体中的ELISA：RIA比率从1.1变化到2.9。高分子量形式的热转变引起其洗脱体积的变化，但没有改变其在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳中的迁移。质谱分析显示两种形式的结果相同。我们得出以下结论：（a）PINP的三聚体结构在37 ℃下不稳定;（B）两种分子形式代表三聚体和单体形式的完整α 1链;（c）热转变是一个持续的体内过程;（d）这在测定技术的选择中很重要。
The N-terminal propeptide of procollagen type I (PINP) appeared in two peaks after size chromatography. The high-molecular weight form was transformed to the low-molecular weight form during incubation at 37 degreesC, whereas the low-molecular weight form remained unchanged. The PINP concentrations in amniotic fluid and sera remained unchanged during 37 degreesC incubation when measured using an ELISA; however, concentrations decreased by 89-93% when measured using an RIA. The ELISA:RIA ratio varied from 1.1 to 2.9 in these fluids because of different size distributions and the inability of the RIA to measure the low-molecular weight form. Thermal transition of the high-molecular weight form caused a change in its elution volume but did not change its migration in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Mass spectrometry revealed identical results for both forms. We reached the following conclusions: (a) the trimeric structure of PINP is unstable at 37 degreesC; (b) the two molecular forms represent intact alpha1 chains in trimeric and monomeric forms; (c) thermal transition is an ongoing in vivo process; and (d) this is important in the choice of assay technology.