Biochemical characterization of human S-nitrosohemoglobin. Effects on oxygen binding and transnitrosation. J Biol Chem 1999 May 28;274(22):15487-92
Date
05/21/1999Pubmed ID
10336440DOI
10.1074/jbc.274.22.15487Scopus ID
2-s2.0-0033016469 (requires institutional sign-in at Scopus site) 126 CitationsAbstract
S-Nitrosation of cysteine beta93 in hemoglobin (S-nitrosohemoglobin (SNO-Hb)) occurs in vivo, and transnitrosation reactions of deoxygenated SNO-Hb are proposed as a mechanism leading to release of NO and control of blood flow. However, little is known of the oxygen binding properties of SNO-Hb or the effects of oxygen on transnitrosation between SNO-Hb and the dominant low molecular weight thiol in the red blood cell, GSH. These data are important as they would provide a biochemical framework to assess the physiological function of SNO-Hb. Our results demonstrate that SNO-Hb has a higher affinity for oxygen than native Hb. This implies that NO transfer from SNO-Hb in vivo would be limited to regions of extremely low oxygen tension if this were to occur from deoxygenated SNO-Hb. Furthermore, the kinetics of the transnitrosation reactions between GSH and SNO-Hb are relatively slow, making transfer of NO+ from SNO-Hb to GSH less likely as a mechanism to elicit vessel relaxation under conditions of low oxygen tension and over the circulatory lifetime of a given red blood cell. These data suggest that the reported oxygen-dependent promotion of S-nitrosation from SNO-Hb involves biochemical mechanisms that are not intrinsic to the Hb molecule.
Author List
Patel RP, Hogg N, Spencer NY, Kalyanaraman B, Matalon S, Darley-Usmar VMAuthors
Neil Hogg PhD Associate Dean, Professor in the Biophysics department at Medical College of WisconsinBalaraman Kalyanaraman PhD Professor in the Biophysics department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
Allosteric RegulationCysteine
Erythrocytes
Ethylmaleimide
Glutathione
Hemoglobins
Humans
Kinetics
Nitrosation
Nitroso Compounds
Oxygen
Penicillamine
S-Nitrosoglutathione
S-Nitrosothiols
Spectrophotometry
Sulfhydryl Compounds
Vasodilation