NEW METHODS FOR NONENZYMATIC PEPTIDE CLEAVAGE . ELECTROLYTIC DIFFERENTIAL + SOLVOLYTIC CLEAVAGE OF ANTIBIOTIC CYCLOPEPTIDE RUFOMYCIN
NEW METHODS FOR NONENZYMATIC PEPTIDE CLEAVAGE . ELECTROLYTIC DIFFERENTIAL + SOLVOLYTIC CLEAVAGE OF ANTIBIOTIC CYCLOPEPTIDE RUFOMYCIN
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DOI：
10.1021/ja01075a035
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发表时间：
1964-01-01
影响因子：
15
通讯作者：
WITKOP, B
中科院分区：
文献类型：
--
作者：
IWASAKI, H;WITKOP, B
抗生素环七肽鲁福霉素 A 含有以下具有反应中心的“双功能”氨基酸，可裂解相邻的肽基团：3-硝基酪氨酸、N,4-二甲基-谷氨酸-y-半醛、A4-正亮氨酸（2-氨基-4-己烯酸）和取代的色氨酸。选择性裂解肽键的以下新原理是详细阐述：(i) 3-硝基三甲酰基键的电解裂解导致释放出高达 38% 的相邻丙氨酸 NH^-末端；(ii) O-甲基二氢卢福霉素 A () 的 O-甲磺酸酯的溶剂裂解导致 53% 选择性裂解为 seco-O-甲基-二氢卢福霉素-内酯 (XI)，并释放相邻的当3-硝基酪氨酸受到O-甲基化保护时，用N-溴代琥珀酰亚胺进行差异氧化，选择性地裂解色氨酸和去氢正亮氨酸旁边的肽键，这种用NBS进行的双重裂解释放出一种新型取代的（5-溴）螺二恶吲哚内酯XX，其特征为其DXP衍生物，并可通过无机酸的作用转化为已知的螺内酯XXI DXP-色氨酸；(iv) 用溴脲进行差异氧化裂解，仅裂解色氨酸，但不裂解脱氢正亮氨酸；(v) 通过 NBS 氧化裂解 DNP-血清-O-甲基二氢芦福霉素 XI，得到二肽 DNP-亮氨酰-2-氨基-4-羟基-5-溴己酸内酯 (XXII)，可以方便地纯化和分离 Rufomyin A。作为硼氢化钠还原产物，二氢紫红霉素 A，很容易从乙醇中结晶。紫红霉素 A 的均质性和纯化。紫红霉素 A 是一种环肽抗生素，对分枝杆菌具有特异性活性，包括对异烟酸酰肼、链霉素和卡那霉素具有抗性的菌株。它与活性较低的紫红霉素 B 一起从链霉菌菌株的培养物中分离出来。两种抗生素 (I、II) 均为环状七肽 3 通过从首先从乙醇溶液中结晶的红霉素 B 母液中蒸发溶剂，获得黄色无定形粉末状的粗品红霉素 A。
The antibiotic cycloheptapeptide rufomycin A contains the following ‘'bifunctional” amino acids possessing reactive centers which are amenable to cleavage of adjacent peptide groups: 3-nitrotyrosine, N, 4-diinethyl-glutamic-y-semialdehyde, A4-norleucine (2-amino-4-hexenoic acid), and a substituted tryptophan. The follow-ing new principles for selective cleavage of peptide bonds were elaborated:(i) electrolytic cleavage of the 3-nitrotvrosyl bond resulted in liberation of up to 38% of the adjacent alanine NH^-terminal;(ii) solvolytic cleavage of the O-mesylate of O-methyldihydrorufomvcin A () resulted in 53% selective cleavage to seco-O-methyl-dihydrorufomycin--lactone (XI) with release of the adjacent leucyl unit;(iii) differential oxidation with N-bromosuccinimide cleaved selectively the peptide bond next to tryptophan and dehvdronorleucine, when 3-nitrotyrosine was protected by O-methylation—this twofold cleavage with NBS released a novel substituted (5-bromo) spirodioxindole lactone XX characterized as its DXP derivative and convertible by the action of mineral acid to the known spirolactone XXI from DXP-tryptophan;(iv) differential oxidative cleavage with bromocarbamide cleaved only next to tryptophan but not dehydronorleucine; and (v) oxidative cleavage of DNP-sero-O-methyldihydrorufomycin XI by NBS yielded the dipeptideDNP-leucyl-2-amino-4-hydroxv-5-bromohexanoic acid lactone (XXII). Rufomyin A is conveniently purified and isolated as the sodium boro-hydride reduction product, dihydrorufomycin A, which readily crystallizes from ethanol.Homogeneity and Purification of Rufomycin A.—Rufomycin A is a cyclic peptide antibiotic specifically active aganst Mycobacteria including the strains resist-ant to isonicotinic acid hydrazide, streptomycin, and kanamycin. It was isolated from the culture of a Strep-tomyces strain together with the less active rufomycin B. Both antibiotics (I, II) are cyclic heptapeptides. 3 Crude rufomycin A was obtained as a yellow amor-phous powderby evaporation of the solvent from the mother liquor of rufomycin B which crystallized first from ethanolic solution.