Reducing O sensitivity in electrochemical nitric oxide releasing catheters: An O-tolerant copper(II)-ligand nitrite reduction catalyst and a glucose oxidase catheter coating.

Electrocatalytic nitric oxide (NO) generation from nitrite (NO) within a single lumen of a dual-lumen catheter using Cu-ligand (Cu-L) mediators have been successful at demonstrating NO's potent antimicrobial and antithrombotic properties to reduce bacterial counts and mitigate clotting under low oxygen conditions (e.g., venous blood).

Electrochemical Generation of Nitric Oxide for Medical Applications.

Over the past 30 years, the significance of nitric oxide (NO) has become increasingly apparent in mammalian physiology. It is biosynthesized by three isoforms of nitric oxide synthases (NOS): neuronal (nNOS), endothelial (eNOS), and inducible (iNOS). Neuronal and eNOS both produce low levels of NO (nM) as a signaling agent and vasodilator, respectively.

A Monohydrosulfidodinitrosyldiiron Complex That Generates NO as a Model for Flavodiiron Nitric Oxide Reductases: Reaction Mechanism and Electronic Structure.

Flavodiiron nitric oxide reductases (FNORs) protect microbes from nitrosative stress under anaerobic conditions by mediating the reduction of nitric oxide (NO) to nitrous oxide (NO). The proposed mechanism for the catalytic reduction of NO by FNORs involves a dinitrosyldiiron intermediate with a [hs-{FeNO}] formulation, which produces NO and a diferric species. Moreover, both NO and hydrogen sulfide (HS) have been implicated in several similar physiological functions in biology and are also known to cross paths in cell signaling.

Functional Models for the Mono- and Dinitrosyl Intermediates of FNORs: Semireduction versus Superreduction of NO.

The reduction of NO to NO by flavodiiron nitric oxide reductases (FNORs) is related to the disruption of the defense mechanism in mammals against invading pathogens. The proposed mechanism for this catalytic reaction involves both nonheme mono- and dinitrosyl diiron(II) species as the key intermediates. Recently, we reported an initial account for NO reduction activity of an unprecedented mononitrosyl diiron(II) complex, [Fe(-Et-HPTB)(NO)(DMF)](BF) () (-Et-HPTB is the anion of N,N,N',N'-tetrakis(2-(l-ethylbenzimidazolyl))-2-hydroxy-1,3-diaminopropane; DMF = dimethylformamide) with [Fe{FeNO}] formulation [Jana et al.

A Structural Model for the Iron-Nitrosyl Adduct of Gentisate Dioxygenase.

We present the synthesis, properties, and characterization of [Fe(T1Et4iPrIP)(NO)(HO)](OTf) () (T1Et4iPrIP = Tris(1-ethyl-4-isopropyl-imidazolyl)phosphine) as a model for the nitrosyl adduct of gentisate 1,2-dioxygenase (GDO). The further characterization of [Fe(T1Et4iPrIP)(THF)(NO)(OTf)](OTf) () which was previously communicated (. , , 5414) is also presented.

Non-Heme Diiron Model Complexes Can Mediate Direct NO Reduction: Mechanistic Insight into Flavodiiron NO Reductases.

Flavodiiron nitric oxide reductases (FNORs), a common enzyme family found in various types of pathogenic bacteria, are capable of reducing nitric oxide (NO) to nitrous oxide (NO) as a protective detoxification mechanism. Utilization of FNORs in pathogenic bacteria helps them survive and proliferate in the human body, thus causing chronic infections. In this paper, we present a new diiron model complex, [Fe((PyPhO)MP)(OPr)](OTf), with bridging propionate ligands (OPr) that is capable of directly reducing NO to NO in quantitative yield without the need to (super)reduce the complex.

Non-heme High-Spin {FeNO} Complexes: One Ligand Platform Can Do It All.

Heme and non-heme iron-nitrosyl complexes are important intermediates in biology. While there are numerous examples of low-spin heme iron-nitrosyl complexes in different oxidation states, much less is known about high-spin (hs) non-heme iron-nitrosyls in oxidation states other than the formally ferrous NO adducts ({FeNO} in the Enemark-Feltham notation). In this study, we present a complete series of hs-{FeNO} complexes using the TMGtren coligand.

The Semireduced Mechanism for Nitric Oxide Reduction by Non-Heme Diiron Complexes: Modeling Flavodiiron Nitric Oxide Reductases.

Flavodiiron nitric oxide reductases (FNORs) are a subclass of flavodiiron proteins (FDPs) capable of preferential binding and subsequent reduction of NO to NO. FNORs are found in certain pathogenic bacteria, equipping them with resistance to nitrosative stress, generated as a part of the immune defense in humans, and allowing them to proliferate. Here, we report the spectroscopic characterization and detailed reactivity studies of the diiron dinitrosyl model complex [Fe(BPMP)(OPr)(NO)](OTf) for the FNOR active site that is capable of reducing NO to NO [Zheng et al.

Functional Mononitrosyl Diiron(II) Complex Mediates the Reduction of NO to NO with Relevance for Flavodiiron NO Reductases.

Reaction of [Fe(N-Et-HPTB)(CHCOS)](BF) (1) with (NO)(BF) produces a nonheme mononitrosyl diiron(II) complex, [Fe(N-Et-HPTB)(NO)(DMF)](BF) (2). Complex 2 is the first example of a [Fe{Fe(NO)}] species and is also the first example of a mononitrosyl diiron(II) complex that mediates the reduction of NO to NO. This work describes the selective synthesis, detailed characterization and NO reduction activity of 2 and thus provides new insights regarding the mechanism of flavodiiron nitric oxide reductases.