Modelling of long-term photoresponse of bacteriorhodopsin immobilized on cellulose acetate membranes

Sediroglu, V
Aydemir, A
Gündüz, Ufuk
Yucel, M
Turker, L
Eroglu, I
Purple membrane fragments with its integrated protein bacteriorhodopsin were immobilized on lipid impregnated and lipid free cellulose acetate membranes. Two mathematical models were suggested to simulate the photoresponse curves of these membranes which were obtained by measuring the pH variation independently in each chamber of a specifically designed photoactivity cell for long periods of illumination. The first order model suggested was mainly based on the existence of light phase deprotonation and dark phase reprotonation reactions. The overall deprotanation rate constants were found to be slightly less than the overall reprotonation rate constants with the first order kinetics. In the second model, the pH change-time data were expressed by a mathematical decay function. There has been found a great agreement between the first order rate constants and the decay constants.


EROGLU, I; ZUBAT, BM; Yücel, Ayşe Meral (1991-09-01)
Purple membrane fragments isolated from the cell membrane of the photosynthetic bacteria Halobacterium halobium S.9 strain are incorporated into egg yolk phosphatidylcholine liposomes. Purple membrane contains crystalline patches of a retinal protein called bacteriorhodopsin. Upon illumination, bacteriorhodopsin undergoes a reversible photoreaction in which a proton is released on one side of the membrane and a proton is bound on the other side, thus resulting in an electro-chemical gradient across the me...
Comparison of antioxidant enzyme activities and DNA damage in chickpea (Cicer arietinum L.) genotypes exposed to vanadium
Imtiaz, Muhammad; Mushtaq, Muhammad Adnan; Rizwan, Muhammad Shahid; Arif, Muhammad Saleem; Yousaf, Balal; Ashraf, Muhammad; Xiong Shuanglian, Xiong Shuanglian; Rizwan, Muhammad; Mehmood, Sajid; Tu, Shuxin (2016-10-01)
The present study was done to elucidate the effects of vanadium (V) on photosynthetic pigments, membrane damage, antioxidant enzymes, protein, and deoxyribonucleic acid (DNA) integrity in the following chickpea genotypes: C-44 (tolerant) and Balkasar (sensitive). Changes in these parameters were strikingly dependent on levels of V, at 60 and 120 mg V L-1 induced DNA damage in Balkasar only, while photosynthetic pigments and protein were decreased from 15 to 120 mg V L-1 and membrane was also damaged. It was...
Investigation of the effect of GPCR oligomerization on the GNAi1 protein homodimerization in live cells using FRET
Nalli, Enise; Son, Çağdaş Devrim; Küçük Baloğlu, Fatma; Department of Biotechnology (2022-1-26)
G-Protein Coupled Receptors (GPCR) are membrane proteins that pass the cell membrane seven times. In classical GPCR signaling pathways, one GPCR-one heterotrimeric G-protein interaction model is enough to transmit the signal to effector proteins. Studies since 2000 showed that one GPCR dimer-one heterotrimeric G-protein interaction model is more likely, and GPCRs having homo- /hetero- dimers interact with a single G⍺-protein. Recently, studies on GPCRs indicated that more than two receptors interact to ...
Integration of clavaminate synthase 2 gene into the chromosome of an industrial strain of Streptomyces Clavuligerus for enhanced clavulanic acid production
Vanlı, Güliz; Özcengiz, Gülay; Özkan, Melek; Department of Biotechnology (2010)
Streptomyces clavuligerus is a gram-positive, filamentous bacterium which has a great ability to produce secondary metabolites including isopenicillin N, cephamycin C and a beta-lactamase inhibitor clavulanic acid. Clavulanic acid (CA) which is a bicyclic beta-lactam, inhibits most of class A beta-lactamases by binding irreversibly to the serine hydroxyl group at the active center of beta-lactamases and resulting in the stable acyl-enzyme complexes. Clavaminate synthase (CAS) is one of the best characterize...
Evaluation of functional changes in akr1b1 and akr1b10 overexpressing colorectal cancer cell lines
Güderer, İsmail; Banerjee, Sreeparna; Department of Biology (2021-2-15)
Aldo-keto reductases (AKRs) are nicotinamide adenine dinucleotide phosphate (NADPH)-dependent enzymes with diverse cellular metabolism functions. AKR1B1 and AKR1B10 are two of the most studied enzymes in the AKR family. AKR1B1 reduces excess glucose into sorbitol using reducing electrons from NADPH, and the hyperactivation of the AKR1B1 pathways is associated with oxidative stress and cell death. AKR1B10 is a poor reductant of glucose but is a vital enzyme that can metabolize retinol and many other drugs an...
Citation Formats
V. Sediroglu, A. Aydemir, U. Gündüz, M. Yucel, L. Turker, and I. Eroglu, “Modelling of long-term photoresponse of bacteriorhodopsin immobilized on cellulose acetate membranes,” JOURNAL OF MEMBRANE SCIENCE, pp. 65–71, 1996, Accessed: 00, 2020. [Online]. Available: