PMID: 45396Feb 1, 1979

The quantum yield of flash-induced proton release by bacteriorhodopsin-containing membrane fragments

Biophysical Journal
D R Ort, W W Parson

Abstract

The quantum yield of proton release by bacteriorhodopsin was measured from volume changes after excitation of purple membrane fragments by short flashes. At low ionic strengths, about 0.25 mol of protons is released per einstein absorbed. This agrees well with quantum yields reported recently for the conversion of bacteriorhodopsin into a metastable state (M) that absorbs near 412 nm. However, the quantum yield of proton release increases gradually with increasing ionic strength; it plateaus with a value of 0.43 +/- 0.03 at ionic strengths above 200 mM. Changing the ionic strength has no detectable effect on the quantum yield of formation of the M spectral state. It thus appears that as many as two protons can be released and rebound in each photochemical cycle at high ionic strengths. The quantum yield of proton release is essentially independent of pH over the range 6.0-8.75. The quantum yield decreases with increasing flash strength, apparently due to photoreversal of the initial photochemical reaction.

Citations

Apr 1, 1992·Journal of Bioenergetics and Biomembranes·J K Lanyi
Jan 1, 1985·The Journal of Membrane Biology·M E DumontF M Richards
Mar 10, 2001·Journal of Photochemistry and Photobiology. B, Biology·K HuY Zhang
Aug 1, 1980·Proceedings of the National Academy of Sciences of the United States of America·C CarmeliL Packer
Jan 1, 1983·Proceedings of the National Academy of Sciences of the United States of America·T Marinetti, D Mauzerall
Nov 1, 1984·Proceedings of the National Academy of Sciences of the United States of America·Q LiT G Ebrey
Mar 1, 1984·Proceedings of the National Academy of Sciences of the United States of America·G S HarbisonR G Griffin
Nov 1, 1983·Archives of Biochemistry and Biophysics·E LamL Packer
Aug 1, 1988·Photochemistry and Photobiology·R Renthal, A Hollub

Related Concepts

Bacteriorhodopsins
Carotenoids
Halobacterium
Hydrogen-Ion Concentration
Mathematics
Osmolality
Quantum Theory
Spectrophotometry

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Synthetic Genetic Array Analysis

Synthetic genetic arrays allow the systematic examination of genetic interactions. Here is the latest research focusing on synthetic genetic arrays and their analyses.

Congenital Hyperinsulinism

Congenital hyperinsulinism is caused by genetic mutations resulting in excess insulin secretion from beta cells of the pancreas. Here is the latest research.

Neural Activity: Imaging

Imaging of neural activity in vivo has developed rapidly recently with the advancement of fluorescence microscopy, including new applications using miniaturized microscopes (miniscopes). This feed follows the progress in this growing field.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Epigenetic Memory

Epigenetic memory refers to the heritable genetic changes that are not explained by the DNA sequence. Find the latest research on epigenetic memory here.

Cell Atlas of the Human Eye

Constructing a cell atlas of the human eye will require transcriptomic and histologic analysis over the lifespan. This understanding will aid in the study of development and disease. Find the latest research pertaining to the Cell Atlas of the Human Eye here.

Femoral Neoplasms

Femoral Neoplasms are bone tumors that arise in the femur. Discover the latest research on femoral neoplasms here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.