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Titolo:
MEASUREMENT OF THE HEMOGLOBIN CONCENTRATION IN DEOXYHEMOGLOBIN-S POLYMERS AND CHARACTERIZATION OF THE POLYMER WATER COMPARTMENT
Autore:
BOOKCHIN RM; BALAZS T; LEW VL;
Indirizzi:
YESHIVA UNIV ALBERT EINSTEIN COLL MED,DEPT MED,1300 MORRIS PK AVE BRONX NY 10461 UNIV CAMBRIDGE,PHYSIOL LAB CAMBRIDGE CB2 3EG ENGLAND
Titolo Testata:
Journal of Molecular Biology
fascicolo: 1, volume: 244, anno: 1994,
pagine: 100 - 109
SICI:
0022-2836(1994)244:1<100:MOTHCI>2.0.ZU;2-5
Fonte:
ISI
Lingua:
ENG
Soggetto:
SICKLE-CELL HEMOGLOBIN;
Keywords:
SICKLE CELL; HEMOGLOBIN S; POLYMERIZATION; POLYMER WATER; RED BLOOD CELL;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
9
Recensione:
Indirizzi per estratti:
Citazione:
R.M. Bookchin et al., "MEASUREMENT OF THE HEMOGLOBIN CONCENTRATION IN DEOXYHEMOGLOBIN-S POLYMERS AND CHARACTERIZATION OF THE POLYMER WATER COMPARTMENT", Journal of Molecular Biology, 244(1), 1994, pp. 100-109

Abstract

Biological polymers contain freely exchangeable water within intermolecular crevices with restricted access to large extrapolymer solutes. Our recent studies highlighted large osmotic effects of such polymer water compartments (PWCs), and their substantial physiological and pathophysiological relevance. The size and accessibility of the PWC are critical parameters determining the polymers' osmotic properties. We report here a new experimental approach to investigate these parameters in deoxyhemoglobin S polymers. The size of the PWC is inversely relatedto the deoxyhemoglobin S concentration in the polymer (C-P). Only an approximation of C-P (approximate to 69 g/dl) was previously available. By analyzing the distribution a of soluble hemoglobin and a large molecular weight (MW) marker (C-14-dextran, MW approximate to 70kDa) in the supernatant and pellet of centrifuged gels, we obtained a reproducible value of C-P. 54.7 (+/-0.7)g/dl. This indicates that 60% of the polymer is composed of a water compartment inaccessible to soluble Hb and other non-interactive macromolecules. The accessibility properties of this PWC to smaller molecules were explored with markers of different MW. Non-interactive markers with MW < 200 kDa diffused freely in the PWC, whereas those with 300 kDa < MW < 1000 kDa showed partial exclusion. Higher MW markers were generally excluded, except molecules withelongated (rather than spherical) shapes or possible interactivity with hemoglobin. These results predict that dense sickle cells would significantly dehydrate on deoxygenation, generating a PWC of up to 60% to 80% of the cell water. Soluble enzymes would concentrate in the residual cytosol. For osmotic equilibrium, most of the ions and low MW substrates would concentrate in the PWC. Oxygenation-deoxygenation would thus cause dynamic oscillations in cell hydration and between states of single and double cytoplasmic water phases, the latter with a substantially altered internal environment. The relevance of such oscillations to the membrane and metabolic abnormalities of dense sickle cells requires further investigation.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/09/20 alle ore 09:24:15