Stability constant determination of sulfur and selenium amino acids with Cu(II) and Fe(II)

A coumarin derivative-Cu2+ complex-based fluorescent chemosensor for detection of biothiols

“…For example, the Cu 2+ ions react with Cys to form a [CuX 2 ] 2+ complex with an equilibrium constant of 10 16.57,58 Moreover, the Cu 2+ ions react with Hcy to form a [CuHY] 2+ complex with an equilibrium constant of 10 13.5 . 59 Compared to the abovementioned reactions, the reactions between the Cu 2+ ions and GSH are more complicated. In particular, the main reaction occurs between the Cu 2+ ions and GSH to generate a complex of Cu + ions with GSH in the form of [CuZ 2 ] + and introduce the GSSG (oxidized glutathione).…”

Speciation study involving mononuclear binary transition metal (CoII, NiII and CuII) complexes of L-methionine in non-ionic micellar medium

“…From literature, the two active sites of Met are binded via carboxylate (-COO -) and amino (-NH 2 ) groups through the respective donor atoms of "O" and "N" with these metal ions create a five membered stable cyclic rings, in which Met acted as a bidentate chelate ligand [29,30,31,32,33,34]. At lower pH, the carboxylate "O" of Met can donate the electron pair to the metal ion forming protonated species, MLH and retaining lone pair of electrons in amino group contributed to the proton.…”

“…At higher pH, the active sites amino and carboxylate bind through the donor atoms 'N' and 'O' of met with the metal ion, thereby forming deprotonated species, ML and ML 2 . Also with the knowledge of valence shell electron pair repulsion theory, the binary complexes of M(Co II , Ni II and Cu II )-Met systems must be octahedral in shape [28], due to the availability of six electron pairs in its outer most shell, which suggests the schematic structures in Figure 3 [29][30][31][32][33][34].…”

“…In addition to its wide applications in biology, Met and derivatives of Met are often utilized in organic reactions as asymmetric catalysts [25,26]. Generally ligand, met behaves like a bidentate through its active sites of amino together with carboxylic acid groups having high affinity to coordinate with these metal ions (Co II , Ni II and Cu II ) [27,28,29,30,31,32,33,34]. Binary complexes of transition metals (Co II , Ni II and Cu II ) of L-methionine in different media are reported earlier by Paper Ionophoretic technique and Potentiometric method [35,36].…”

Взаимодействие Базидиомицетов С Переменно-Валентными Элементами В Составе Аспартатов Биогенных Металлов(ii)

“…Ионы металлов связываются с карбоксильными группами, а в комплексах аспарагиновой кислоты некоторые ионы металлов способны образовывать хелатную связь с аминогруппами (19,20). Поэтому для ряда металлокомплексов аспарагиновой кислоты константы устойчивости в основном определяются сродством ионов металлов к аминогруппе (21), что приводит к избирательному связыванию ионов металлов и их переносу в комплексе с аспартатом (22,23). Благодаря металл-координированному состоянию микроэлементов наблюдается повышение усвоения минеральных веществ организмом (24).…”