Analysis of the kinetics of CO binding to neuronal nitric oxide synthase by flash photolysis: dual effects of substrates, inhibitors, and tetrahydrobiopterin

Bengea, Simona; Araki, Yasuyuki; Ito, Osamu; Igarashi, Jun–ichi; Sagami, Ikuko; Shimizu, Tôru

doi:10.1016/j.jinorgbio.2004.04.009

Cited by 6 publications

(3 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We studied NO dissociation from pre‐formed ferrous heme–NO complexes of the oxygenase domains of iNOS (iNOSoxy) and nNOS (nNOSoxy) using sodium dithionite as an NO scavenger in the presence of CO. When NO dissociates from the NOS heme, CO binds quickly [13–16] to form a heme Fe II –CO complex, which can be followed by a shift in the heme Soret absorbance from 436 to 445 nm. Spectral analyses of the NO dissociation reactions for nNOSoxy and iNOSoxy are shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Fast ferrous heme–NO oxidation in nitric oxide synthases

2009

View full text Add to dashboard Cite

During catalysis, the heme in nitric oxide synthase (NOS) binds NO before releasing it to the environment. Oxidation of the NOS ferrous heme–NO complex by O2 is key for catalytic cycling, but the mechanism is unclear. We utilized stopped‐flow methods to study the reaction of O2 with ferrous heme–NO complexes of inducible and neuronal NOS enzymes. We found that the reaction does not involve heme–NO dissociation, but instead proceeds by a rapid direct reaction of O2 with the ferrous heme–NO complex. This behavior is novel and may distinguish heme–thiolate enzymes, such as NOS, from related heme proteins.

show abstract

Section: Resultsmentioning

confidence: 99%

Fast ferrous heme–NO oxidation in nitric oxide synthases

2009

View full text Add to dashboard Cite

show abstract

“…Previous studies have used the Bedfont breathalyzer to measure levels of CO in NTS and NTN volunteers [25]. A concern for this test is the time frame for analysis relative to the volunteer's last cigarette; CO in the body has a half-life of three to four hours [21]. In our study, the mean elapsed time since last cigarette smoked was 1.85 hours, with the longest reported elapsed time being 4 hours.…”

Section: Discussionmentioning

confidence: 58%

“…The sensitivity and specificity of this device has been previously reported in pregnant women, with a cut off value set at 5 ppm to differentiate smokers and nonsmokers [20]. Using the reported time since last cigarette, we corrected the ETCO levels of each subject, assuming a 3 hr CO half-life [21]. These corrected values are used in all analyses.…”

Section: Sample Collectionmentioning

confidence: 99%

Self-reported cigarette smoking status imprecisely quantifies exposure in pregnancy

Venditti¹,

Smith

2012

OJOG

View full text Add to dashboard Cite

Objective: We sought to determine the validity of self-reported smoking activity versus two quantitative measurements of tobacco exposure in pregnancy. We hypothesized that pregnant women would under-report their daily smoking amounts, due to the negative social stigmas associated with such a behavior. Methods: Cigarette-smoking and non-smoking pregnant women were recruited as part of a larger research study. Pregnant women with a singleton baby (>24 weeks) were recruited at a clinical appointment or prior to an elective caesarian section. Self-reported smoking status, including time since last cigarette, was recorded. End-tidal breath carbon monoxide (ETCO) levels and urine cotinine levels were measured and compared. Results: Both normotensive non-smoking (NTN) (n = 44) and normotensive smoking (NTS) (n = 24) pregnant women were recruited. A strong correlation was found between ETCO levels and urine cotinine measurements (r = 0.6566, p < 0.05). Self-reported smoking status in NTS was poorly correlated with ETCO levels (r = 0.5356, p < 0.05) and urine cotinine levels (r = 0.0324, P > 0.05). Conclusion: Self-reported smoking status accurately identifies women who smoke in pregnancy, but not their level of tobacco exposure. Urine cotinine or ETCO are much better quantitative measurements of nicotine and carbon monoxide, respectively, and should be measured for a more precise indicator of smoking activity. These devices will allow for better counseling and monitoring of women who are trying to quit smoking and/or who enter into smoking cessation programs

show abstract

Carbon Monoxide Transport and Actions in Blood and Tissues

Thom

2011

Comprehensive Physiology

View full text Add to dashboard Cite

This chapter will discuss the transport of carbon monoxide (CO) from the environment to the tissues of the body and physiological effects on blood-borne cells and perivascular tissues. It will review the physiology of CO exchange between alveolar gas and pulmonary capillary blood, dynamics of hemoglobin transport, the effects of CO on blood elements, and the effects of CO on extravascular tissues at the capillary bed. Effects of CO from exogenous and endogenous sources on the activities of different proteins will be reviewed. Because CO binds competitively to heme-containing proteins its effects depend on CO concentration relative to alternative ligands. Therefore, some discussion is devoted to how nitric oxide and hydrogen sulfide influence CO effects.

show abstract

Analysis of the kinetics of CO binding to neuronal nitric oxide synthase by flash photolysis: dual effects of substrates, inhibitors, and tetrahydrobiopterin

Cited by 6 publications

References 24 publications

Fast ferrous heme–NO oxidation in nitric oxide synthases

Fast ferrous heme–NO oxidation in nitric oxide synthases

Self-reported cigarette smoking status imprecisely quantifies exposure in pregnancy

Carbon Monoxide Transport and Actions in Blood and Tissues

Contact Info

Product

Resources

About