title: Thioester hydrolysis reactivity of zinc hydroxide complexes: investigating reactivity relevant to glyoxalase II enzymes.
abstract: A recently reported binuclear zinc hydroxide complex [(L(1)Zn(2))(mu-OH)](ClO(4))(2) (, L(1) = 2,6-bis[(bis(2-pyridylmethyl)amino)methyl]-4-methylphenolate monoanion) containing a single bridging hydroxide was examined for thioester hydrolysis reactivity. Treatment of it with hydroxyphenylthioacetic acid S-methyl ester in dry CD(3)CN results in no reaction after approximately 65 h at 45(1) degrees C. Binuclear zinc hydroxide complexes of the N-methyl-N-((6-neopentylamino-2-pyridyl)methyl)-N-((2-pyridyl)methyl)amine (L(2)) and N-methyl-N-((6-neopentylamino-2-pyridyl)methyl)-N-((2-pyridyl)ethyl)amine (L(3)) chelate ligands were prepared by treatment of each ligand with molar equivalent amounts of Zn(ClO(4))(2).6H(2)O and KOH in methanol. These complexes, [(L(2)Zn)(2)(mu-OH)(2)](ClO(4))(2) and [(L(3)Zn)(2)(mu-OH)(2)](ClO(4))(2) (), which have been structurally characterized by X-ray crystallography, behave as 1 : 1 electrolytes in acetonitrile, indicating that the binuclear cations dissociate into monomeric zinc hydroxide species in solution. Treatment of them with one equivalent of hydroxyphenylthioacetic acid S-methyl ester per zinc center in acetonitrile results in the formation of a zinc alpha-hydroxycarboxylate complex, [(L(2))Zn(O(2)CCH(OH)Ph)]ClO(4).1.5H(2)O or [(L(3))Zn(O(2)CCH(OH)Ph)]ClO(4).1.5H(2)O, and CH(3)SH. These reactions, to our knowledge, are the first reported examples of thioester hydrolysis mediated by zinc hydroxide complexes. The results of this study suggest that a terminal Zn-OH moiety may be required for hydrolysis reactivity with a thioester substrate.
authors.affiliation: Department of Chemistry and Biochemistry, Utah State University, 0300 Old Main Hill, Logan, UT 84322-0300, USA. berreau@cc.usu.edu
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Berreau
authors.forename: Amrita
authors.initials: A
authors.lastname: Saha
authors.forename: Atta M
authors.initials: AM
authors.lastname: Arif
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry; D006868:Hydrolysis; D006878:Hydroxides / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D013463:Sulfuric Acid Esters / Q000737:chemistry*; D013869:Thiolester Hydrolases / Q000737:chemistry; D017967:Zinc Compounds / Q000737:chemistry*; D000099301:Hydroxyacylglutathione Hydrolase
chemical_list: D006878:Hydroxides; D009942:Organometallic Compounds; D013463:Sulfuric Acid Esters; D013869:Thiolester Hydrolases; D017967:Zinc Compounds; D000099301:Hydroxyacylglutathione Hydrolase; C052745:zinc hydroxide