One-pot biotransformations give oligo(γ-
L
-Et-Glu) decorated with selected amine-functionalized end-groups at C-termini with a first process controlling the end group structure of peptides synthesized by protease catalyzed peptide synthesis, and a second process incorporating end-groups that can be used directly or after further modification as polymerizable entities. Papain, bromelain, α-chymotrypsin, Multifect P-3000 and Purafect prime 4000L are used as catalysts for oligomerization of γ-
L
-(Et)
2
-Glu in the presence of mono functional amines. The series of amine nucleophiles (NH
2
—R, acyl acceptors) mimic phenylalanine in that they possess aromatic rings linked to amine groups by one or more methylenes. Generally, addition of increased quantities of NH
2
—R from 0 to 30, 50 and 70 mol % with respect to γ-
L
-(Et)
2
-Glu results in decreased %-yield but increased mol % of NH
2
—R end-capped oligo(γ-
L
-Et-Glu)-NH—R (determined by NMR). Irrespective of the protease used, 2-thiophene methyl amine (TPMA) gave the highest fraction of oligo(γ-
L
-Et-Glu)-NH—R chains. l-phenylalanine and
L
-histidine did not produce end-capped oligo(γ-
L
-Et-Glu) and, inn contrast,
L
-phenylalanine analogs benzylamine (BzA) and
L
-phenylalaminol (F—OH), both of which lack the α-carboxyl group, gave substantial quantities of oligo(γ-
L
-Et-Glu)-F—OH, or -BzA chains. The promiscuity of proteases can be exploited to create a diverse family of desired end-functionalized oligopeptides. MALDI-TOF spectra recorded of oligo(γ-
L
-Et-Glu) with amine nucleophiles showed molecular ions that affirmed the formation of corresponding NH
2
—R functionalized oligo(γ-
L
-Et-Glu).
一锅法
生物转化反应可在C-末端以选择的胺基官能团修饰的寡聚(γ-L-Et-Glu)上进行,第一个过程控制了
蛋白酶催化合成肽的末端基团结构,第二个过程则将可直接使用或经过进一步修饰后用作聚合物化实体的末端基团结构合并进来。在单官能胺的存在下,Papain、bromelain、α-胰
蛋白酶、Multifect P-3000和Purafect prime 4000L被用作γ-L-(Et)2-Glu的寡聚化催化剂。一系列胺亲核试剂(NH2—R,酰基受体)模仿苯丙
氨酸,因为它们具有芳香环,该芳香环通过一个或多个亚甲基与胺基相连。通常,将NH2—R的量从0增加到30、50和70摩尔%与γ-L-(Et)2-Glu相比,会导致产率下降但NH2—R末端封闭的寡聚(γ-L-Et-Glu)-NH—R的摩尔%增加(通过NMR确定)。无论使用哪种
蛋白酶,2-
噻吩甲基胺(T
PMA)都给出了NH2—R功能化寡聚(γ-L-Et-Glu)链的最高分数。
L-苯丙氨酸和
L-组氨酸不会产生末端封闭的寡聚(γ-L-Et-Glu),相反,
L-苯丙氨酸类似物
苄胺(BzA)和
L-苯丙氨醇(F—OH)(两者都缺少α-羧基)产生了大量的寡聚(γ-L-Et-Glu)-F—OH或-BzA链。
蛋白酶的多样性可以被利用来创建所需的末端官能化寡肽家族。与胺亲核试剂一起记录的MALDI-TOF光谱显示了分子离子,证实了相应的NH2—R功能化寡聚(γ-L-Et-Glu)的形成。