title: Electrochemically driven biocatalysis of the oxygenase domain of neuronal nitric oxide synthase in indium tin oxide nanoparticles/polyvinyl alcohol nanocomposite.
abstract: Nitric oxide synthase (NOS) plays a critical role in a number of key physiological and pathological processes. Investigation of electron-transfer reactions in NOS would contribute to a better understanding of the nitric oxide (NO) synthesis mechanism. Herein, we describe an electrochemically driven catalytic strategy, using a nanocomposite that consisted of the oxygenase domain of neuronal NOS (D290nNOSoxy), indium tin oxide (ITO) nanoparticles and polyvinyl alcohol (PVA). Fast direct electron transfer between electrodes and D290nNOSoxy was observed with the heterogeneous electron transfer rate constant (ket) of 154.8 ± 0.1s(-1) at the scan rate of 5 Vs(-1). Moreover, the substrate N(ω)-hydroxy-L-arginine (NHA) was used to prove the concept of electrochemically driven biocatalysis of D290nNOSoxy. In the presence of the oxygen cosubstrate and tetrahydrobiopterin (BH4) cofactor, the addition of NHA caused the decreases of both oxidation current at +0.1 V and reduction current at potentials ranging from -0.149 V to -0.549 V vs Ag/AgCl. Thereafter, a series of control experiments such as in the absence of BH4 or D290nNOSoxy were performed. All the results demonstrated that D290nNOSoxy biocatalysis was successfully driven by electrodes in the presence of BH4 and oxygen. This novel bioelectronic system showed potential for further investigation of NOS and biosensor applications.
authors.affiliation: School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, PR China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Xu
authors.forename: Ulla
authors.initials: U
authors.lastname: Wollenberger
authors.forename: Jing
authors.initials: J
authors.lastname: Qian
authors.forename: Katrin
authors.initials: K
authors.lastname: Lettau
authors.forename: Christiane
authors.initials: C
authors.lastname: Jung
authors.forename: Songqin
authors.initials: S
authors.lastname: Liu
mesh_terms: D055162:Biocatalysis; D001708:Biopterins / Q000031:analogs & derivatives / Q000737:chemistry; D015374:Biosensing Techniques; D004566:Electrodes; D004583:Electrons; D006801:Humans; D053761:Nanocomposites / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D009474:Neurons / Q000201:enzymology; D009569:Nitric Oxide / Q000096:biosynthesis* / Q000737:chemistry; D052248:Nitric Oxide Synthase Type I / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D010105:Oxygenases / Q000737:chemistry; D011142:Polyvinyl Alcohol / Q000737:chemistry; D017434:Protein Structure, Tertiary; D017971:Tin Compounds / Q000737:chemistry
chemical_list: D017971:Tin Compounds; D001708:Biopterins; D009569:Nitric Oxide; C109984:indium tin oxide; D011142:Polyvinyl Alcohol; D010105:Oxygenases; C496320:NOS1 protein, human; D052248:Nitric Oxide Synthase Type I; C003402:sapropterin; D010100:Oxygen
keywords: Biocatalysis; Indium tin oxide nanoparticles; N(ω)-hydroxy-l-arginine; Nitric oxide synthase; Tetrahydrobiopterin