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Remarkable reactivity of alkoxide/acetato-bridged binuclear copper(II) complex as artificial carboxylesterase.
- Source :
-
Journal of Biological Inorganic Chemistry (JBIC) . Jun2017, Vol. 22 Issue 4, p625-635. 11p. - Publication Year :
- 2017
-
Abstract
- Bromo-containing binuclear Schiff base copper(II) complex, CuL(OAc), with an alkoxo/acetato-bridged moiety was employed as a model of carboxylesterases to promote the hydrolytic cleavage of p-nitrophenyl picolinate (PNPP). Furthermore, the reactivity of a mononuclear complex (CuHL) was evaluated for comparing it with that of binuclear one. The results reveal that the as-prepared binuclear CuL(OAc) efficiently accelerated the hydrolysis of PNPP, giving rise to excess four orders of magnitude rate enhancement in contrast to the un-catalyzed reaction. CuL(OAc) represented an enzyme-like bell-shaped pH-responsive kinetic behavior. Moreover, the binuclear one is more reactive than its mononuclear analogue (CuHL) by two orders of magnitude. The total efficiency of CuL(OAc) is about 61-fold than that of its mononuclear analogue, CuHL. In addition, a contrast experiment reveals that binuclear CuL(OAc) displayed good activity in the hydrolysis of PNPP as well another active ester, i.e., S-2-benzothiazolyl 2-amino-alpha-(methoxyimino)-4-thiazolethiolacetate (AE-active ester). Noteworthyly, it was found that mononuclear one inspired more obvious rate enhancement in the hydrolysis of AE-active ester relative to PNPP hydrolysis. The estimated p K of bound water on the binuclear CuL(OAc) using second derivative method (SDM) is relatively smaller than that for CuHL by a gap of about 0.8 pK unit, which facilitates the hydrolysis of PNPP. Graphical Abstract: Four orders of magnitude rate enhancement was observed for the catalytic hydrolysis of p-nitrophenyl picolinate (PNPP) by one μ-alkoxide/acetato-bridged binuclear copper(II) complex under physiological conditions. Substrate specificity of the resulting binuclear complexes was observed for the hydrolysis of PNPP and AE-active ester. [ABSTRACT FROM AUTHOR]
- Subjects :
- *CARBOXYLESTERASES
*ALKOXIDES
*COPPER
*NITROPHENYL compounds
*HYDROLYSIS
Subjects
Details
- Language :
- English
- ISSN :
- 09498257
- Volume :
- 22
- Issue :
- 4
- Database :
- Academic Search Index
- Journal :
- Journal of Biological Inorganic Chemistry (JBIC)
- Publication Type :
- Academic Journal
- Accession number :
- 123203964
- Full Text :
- https://doi.org/10.1007/s00775-017-1456-1