Huebner V D, Jiang R L, Lee T D, Legesse K, Walsh J H, Shively J E, Chew P, Azumi T, Reeve J R
Beckman Research Institute of the City of Hope, Duarte, California 91010.
J Biol Chem. 1991 Jul 5;266(19):12223-7.
Several peptides derived from the gastrin-predicted preprohormone sequence were isolated from a human gastrinoma by gel permeation, anion exchange, and reverse phase chromatography. The peptides were identified and characterized structurally by a combination of radioimmunoassays, mass spectral analysis, and microsequence analysis. The largest peptide, progastrin-(1-35) (cryptagastrin), extends from the putative processing site for the signal peptidase to the double basic residues adjacent to the amino terminus of gastrin 34. A shorter form of this peptide, progastrin-(6-35) (cryptagastrin-(6-35), was also isolated in smaller amounts. In addition, sulfated and nonsulfated gastrin 17 amides (progastrin-(55-71)) and the glycine-extended nonsulfated gastrin 17 (progastrin-(55-72)) were identified by radioimmunoassay, and their structures were confirmed by mass spectral analysis. Isolation of cryptagastrin indicates that the signal peptide of human preprogastrin contains 21 amino acid residues, and progastrin, therefore, contains 80 amino acids. There is minimal processing of the cryptic peptide preceding the sequence of gastrin 34. An amidated gastrin form larger than gastrin 34 could contain 71 amino acids. No evidence was obtained for processing that would produce gastrins containing more than 34 but less than 71 amino acid residues.
通过凝胶渗透、阴离子交换和反相色谱法，从一例人胃泌素瘤中分离出了几种源自胃泌素预测前体激素序列的肽段。通过放射免疫测定、质谱分析和微序列分析相结合的方法，对这些肽段进行了结构鉴定和表征。最大的肽段，即胃泌素原-（1-35）（隐胃泌素），从信号肽酶的假定加工位点延伸至与胃泌素34氨基末端相邻的双碱性残基。该肽段的一种较短形式，胃泌素原-（6-35）（隐胃泌素-（6-35）），也以较少的量被分离出来。此外，通过放射免疫测定鉴定出了硫酸化和非硫酸化的胃泌素17酰胺（胃泌素原-（55-71））以及甘氨酸延伸的非硫酸化胃泌素17（胃泌素原-（55-72）），并通过质谱分析证实了它们的结构。隐胃泌素的分离表明人前胃泌素原的信号肽含有21个氨基酸残基，因此胃泌素原含有80个氨基酸。在胃泌素34序列之前的隐肽加工极少。一种比胃泌素34更大的酰胺化胃泌素形式可能含有71个氨基酸。未获得产生含有超过34个但少于71个氨基酸残基的胃泌素的加工证据。
