Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
ENTHALPY CHANGES IN THE FORMATION OF THE PROTON ELECTROCHEMICAL POTENTIAL AND ITS COMPONENTS
Autore:
PU RY; WANG Y; CHEN CH;
Indirizzi:
NEW YORK STATE DEPT HLTH,WADSWORTH CTR LABS & RES ALBANY NY 12201 NEW YORK STATE DEPT HLTH,WADSWORTH CTR LABS & RES ALBANY NY 12201 SUNY ALBANY,DEPT CHEM ALBANY NY 12201 SUNY ALBANY,DEPT BIOMED SCI ALBANY NY 12201
Titolo Testata:
Biophysical chemistry
fascicolo: 3, volume: 53, anno: 1995,
pagine: 283 - 290
SICI:
0301-4622(1995)53:3<283:ECITFO>2.0.ZU;2-G
Fonte:
ISI
Lingua:
ENG
Soggetto:
LACTOSE ACTIVE-TRANSPORT; PROTEIN-SALT INTERACTION; D-LACTATE DEHYDROGENASE; COLI MEMBRANE-VESICLES; ESCHERICHIA-COLI; ENERGETICS; PHYCOCYANIN; MECHANISM; NIGERICIN; GRADIENT;
Keywords:
MEMBRANE POTENTIAL; MICROCALORIMETRY; THERMODYNAMICS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
34
Recensione:
Indirizzi per estratti:
Citazione:
R.Y. Pu et al., "ENTHALPY CHANGES IN THE FORMATION OF THE PROTON ELECTROCHEMICAL POTENTIAL AND ITS COMPONENTS", Biophysical chemistry, 53(3), 1995, pp. 283-290

Abstract

Enthalpy changes in the formation of a proton electrochemical potential (Delta ($) over bar mu(H+)) and its components, Delta pH (proton gradient) and Delta psi (electrical potential), across two types of E. coli membrane vesicles were investigated. Flow dialysis experiments showed that in 0.1 M KPi, pH 6.6, E. coli GR19N membrane vesicles coupledwith D-lactate exhibited 57 mV for Delta pH, 70 mV for Delta psi, and127 mV for Delta ($) over bar mu(H). Microcalorimetric measurements revealed that the corresponding enthalpy changes (Delta H-pH, Delta H-psi and Delta H-m) were 3.5, 3.3 and 6.9 kcal/mole, respectively. Moreover, in E. coli ML 308-225 membrane vesicles across which 120 mV of Delta ($) over bar mu(H+) was generated, values of Delta H-pH Delta H-psi were determined as 7.0 and 6.6 kcal/mole, as compared with the previously reported 14.1 kcal/mole for Delta H-m. Comparisons of these enthalpy data revealed the component enthalpies (Delta H-pH and Delta H-psi) essentially added up to the total enthalpy (Delta H-m), providing aself-consistent test for the obtained data. In both membranes, the ratio of Delta H-psi to Delta psi was comparable to that of Delta H-pH to Delta pH in the formation of Delta ($) over bar mu(H+). These observations indicated that the process of the movement of H+ across the membranes was the major contributor to the observed energetic changes. Moreover, the enthalpy change in the formation of Delta ($) over bar mu(H+) was compared with the membranes derived from GR19N and ML 308-225 and coupled with NADH and D-lactate. The results were discussed in terms of trans-membrane phenomena.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 03/12/20 alle ore 14:31:30