Switch to
| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
30
|
| pubmed:dateCreated |
1998-8-20
|
| pubmed:abstractText |
The S-conjugation rates of the free-reacting thiols present on each component of rat hemoglobin with 5,5-dithio-bis(2,2-nitrobenzoic acid) (DTNB) have been studied under a variety of conditions. On the basis of their reactivity with DTNB (0.5 mM), three classes of thiols have been defined as follows: fast reacting (fHbSH), with t1/2 <100 ms; slow reacting (sHbSH), with t1/2 30-50 s; and very slow reacting (vsHbSH), with t1/2 180-270 s. Under paraphysiological conditions, fHbSH (identified with Cys-125beta(H3)) conjugates with DTNB 100 times faster than glutathione and approximately 4000 times more rapidly than (v)sHbSH (Cys-13alpha(A11) and Cys-93beta(F9)). Such characteristics of fHbSH reactivity that are independent of the quaternary state of hemoglobin are mainly due to the following: (i) its low pK (approximately 6.9, the cysteinyl anion being stabilized by a hydrogen bond with Ser-123beta(H1)) and (ii) the large exposure to the solvent (as measured by analysis of a model of the molecular surface) and make these thiols the kinetically preferred groups in rat erythrocytes for S-conjugation. In addition, because of the high cellular concentration (8 mM, i.e. four times that of glutathione), fHbSHs are expected to intercept damaging species in erythrocytes more efficiently than glutathione, thus adding a new physiopathological role (direct involvement in cellular strategies of antioxidant defense) to cysteinyl residues in proteins.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Cysteine,
http://linkedlifedata.com/resource/pubmed/chemical/Diamide,
http://linkedlifedata.com/resource/pubmed/chemical/Disulfides,
http://linkedlifedata.com/resource/pubmed/chemical/Dithionitrobenzoic Acid,
http://linkedlifedata.com/resource/pubmed/chemical/Glutathione,
http://linkedlifedata.com/resource/pubmed/chemical/Hemoglobins,
http://linkedlifedata.com/resource/pubmed/chemical/Oxidants,
http://linkedlifedata.com/resource/pubmed/chemical/Sulfhydryl Compounds,
http://linkedlifedata.com/resource/pubmed/chemical/Sulfhydryl Reagents
|
| pubmed:status |
MEDLINE
|
| pubmed:month |
Jul
|
| pubmed:issn |
0021-9258
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
24
|
| pubmed:volume |
273
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
19198-206
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading |
pubmed-meshheading:9668107-Animals,
pubmed-meshheading:9668107-Cysteine,
pubmed-meshheading:9668107-Diamide,
pubmed-meshheading:9668107-Disulfides,
pubmed-meshheading:9668107-Dithionitrobenzoic Acid,
pubmed-meshheading:9668107-Erythrocytes,
pubmed-meshheading:9668107-Glutathione,
pubmed-meshheading:9668107-Hemoglobins,
pubmed-meshheading:9668107-Male,
pubmed-meshheading:9668107-Models, Molecular,
pubmed-meshheading:9668107-Oxidants,
pubmed-meshheading:9668107-Oxidative Stress,
pubmed-meshheading:9668107-Protein Conformation,
pubmed-meshheading:9668107-Rats,
pubmed-meshheading:9668107-Rats, Sprague-Dawley,
pubmed-meshheading:9668107-Structure-Activity Relationship,
pubmed-meshheading:9668107-Sulfhydryl Compounds,
pubmed-meshheading:9668107-Sulfhydryl Reagents
|
| pubmed:year |
1998
|
| pubmed:articleTitle |
Fast-reacting thiols in rat hemoglobins can intercept damaging species in erythrocytes more efficiently than glutathione.
|
| pubmed:affiliation |
Istituto di Clinica delle Malattie Nervose e Mentali, Sezione di Farmacologia, Università di Siena, 53100 Siena, and Centro di Biologia Molecolare, CNR, 00185 Roma, Italy.
|
| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|