Rehfeld J F, Andersen B N, Petersen B
Scand J Gastroenterol Suppl. 1983;82:19-24.
Molecular heterogeneity is a fundamental feature of ribosomally synthesized proteins and polypeptides. The heterogeneity reflects gene duplications with subsequent differences in mutation of the genes, different post-transcriptional and post-translational processings and different amino acid modifications. Gut hormones are also heterogeneous, but the degree of heterogeneity reported so far for each hormone has varied. The most extensively studied (i.e. cholecystokinins, gastrins, opioid peptides and glucagons) have displayed a high degree off heterogeneity. Similar degrees will probably emerge for the remaining gut hormones when they have been studied in greater detail. In accordance with the nature of the molecular difference, a distinction between macro- and microheterogeneity is proposed. Macroheterogeneity is caused by variations in peptide chain length; microheterogeneity by derivatizations or substitutions in single amino acid residues. The molecular heterogeneity has profound implications for measurement and study of a gut hormone. Thus, measurement in biological fluids requires careful evaluation of the number and affinity of different molecular forms. Understanding of the function and pathophysiology of gut hormones requires full clarification of their molecular heterogeneity.
分子异质性是核糖体合成的蛋白质和多肽的一个基本特征。这种异质性反映了基因复制以及随后基因在突变上的差异、不同的转录后和翻译后加工过程以及不同的氨基酸修饰。胃肠激素也具有异质性，但迄今为止报道的每种激素的异质性程度各不相同。研究最为广泛的（即缩胆囊素、胃泌素、阿片肽和胰高血糖素）已表现出高度的异质性。当对其余胃肠激素进行更详细的研究时，可能也会出现类似程度的异质性。根据分子差异的性质，提出了宏观异质性和微观异质性之间的区分。宏观异质性是由肽链长度的变化引起的；微观异质性则是由单个氨基酸残基的衍生化或取代引起的。分子异质性对胃肠激素的测量和研究具有深远影响。因此，在生物体液中进行测量需要仔细评估不同分子形式的数量和亲和力。要了解胃肠激素的功能和病理生理学，就需要充分阐明它们的分子异质性。
