fulltext.study @t Gmail

Does photodissociation of molecular oxygen from myoglobin and hemoglobin yield singlet oxygen?

Paper ID Volume ID Publish Year Pages File Format Full-Text
30638 44494 2013 12 PDF Available
Title
Does photodissociation of molecular oxygen from myoglobin and hemoglobin yield singlet oxygen?
Abstract

Time-resolved luminescence measurements in the near-infrared region indicate that photodissociation of molecular oxygen from myoglobin and hemoglobin does not produce detectable quantities of singlet oxygen. A simple and highly sensitive method of luminescence quantification is developed and used to determine the upper limit for the quantum yield of singlet oxygen production. The proposed method was preliminarily evaluated using model data sets and confirmed with experimental data for aqueous solutions of 5,10,15,20-tetrakis(4-N-methylpyridyl) porphyrin. A general procedure for error estimation is suggested. The method is shown to provide a determination of the integral luminescence intensity in a wide range of values even for kinetics with extremely low signal-to-noise ratio. The present experimental data do not deny the possibility of singlet oxygen generation during the photodissociation of molecular oxygen from myoglobin and hemoglobin. However, the photodissociation is not efficient to yield singlet oxygen escaped from the proteins into the surrounding medium. The upper limits for the quantum yields of singlet oxygen production in the surrounding medium after the photodissociation for oxyhemoglobin and oxymyoglobin do not exceed 3.4 × 10−3 and 2.3 × 10−3, respectively. On the average, no more than one molecule of singlet oxygen from every hundred photodissociated oxygen molecules can succeed in escaping from the protein matrix.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► 1O2 is not observed at the photodissociation of O2 from myoglobin and hemoglobin. ► A simple and highly sensitive method of luminescence quantification is reported. ► A kinetic model for the 1O2 generation and subsequent deactivation is discussed. ► The upper limit for the quantum yield of 1O2 generation is determined.

Keywords
Singlet oxygen; Myoglobin; Hemoglobin; Photodissociation; Luminescence; Quantum yield
First Page Preview
Does photodissociation of molecular oxygen from myoglobin and hemoglobin yield singlet oxygen?
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 120, 5 March 2013, Pages 130–141
Authors
, , , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us