GRAMICIDIN A .V. STRUCTURE OF VALINE-AND ISOLEUCINE-GRAMICIDIN A
GRAMICIDIN A .V. STRUCTURE OF VALINE-AND ISOLEUCINE-GRAMICIDIN A
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DOI：
10.1021/ja01087a027
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发表时间：
1965-01-01
影响因子：
15
通讯作者：
WITKOP, B
中科院分区：
文献类型：
--
作者：
SARGES, R;WITKOP, B
短杆菌肽A是线性N-酰化十五肽乙醇酰胺。它的N-末端L-缬氨酸或C-异亮氨酸被甲酰基封闭，甲酰基在室温下通过温和的甲醇分解而裂解，并且很容易通过气相色谱法鉴定为甲酸或通过变色酸测定法还原后鉴定为甲醛。去甲酰基短杆菌肽A经O-甲酰短杆菌肽A复性得到短杆菌肽A。去甲酰基短杆菌肽A进行了10个连续的埃德曼降解条件下修改，以适应其残留的肽片段在水中的不溶性。通过气相色谱法分析通过用三氟乙酸环化获得的苯硫代乙内酰脲，直至步骤10。此外，对第10步的残肽进行了水解，并定量测定了其氨基酸。短杆菌肽A中四个色氨酸后的键的选择性N-溴琥珀酰亚胺（NBS）断裂释放出氨基乙醇和亮氨酰色氨酸的NBS氧化产物，但没有预期的二氧吲哚丙氨酸螺内酯片段Jrom a
Gramicidin A is a linear N-acylated pentadecapeptide ethanolamide. ItsN-terminal L-valine or c-isoleucine are blocked by a formyl group which is cleavedby mild methanolysis at room temperature and easily identified as formic acidby gas chromatography or as formaldehyde after reduction by the chromotropic acid assay. Re-formylation of desformy¡ gramicidin A, via O-formylgramicidin A, gave back gramicidin A. Desformylgramicidin A was subjected to ten successive Edman degradations under conditions modified to accommodate the insolubility of its residual peptide fragments in water. The phenylthiohydantoins, obtained by cyclization with trifluoroacetic acid, were assayed by gas chromatography up to step 10. In addition, the residual peptides up to step 10 were hydrolyzed and their amino acids determinedquantitatively. Selective N-bromosuccinimide (NBS) cleavage of the bonds following the four tryptophans in gramicidin A releases aminoethanol and the NBS-oxidation product of leucyltryptophan but no dioxindolalanine spirolactone fragment expected Jrom a