PMID: 3607232May 9, 1987

The kinetics of binding of o-methyl red to the outer surface of unilamellar spherical phospholipid vesicles

Biophysical Chemistry
H Ruf

Abstract

The kinetics of adsorption of the proton carrier o-methyl red to the surface of unilamellar spherical phospholipid vesicles have been investigated by means of the temperature-jump relaxation technique with absorbance detection. Single-exponential relaxation curves were observed with time constants in the range 30-130 microseconds. o-Methyl red binds in both its anionic form A- and protonated form AH. Adsorption-desorption of the two species is coupled by two fast protolytic reactions, occurring in the aqueous bulk phase and in the surface region of the membrane. The rate constants for adsorption and desorption of the two species were obtained from the dependences of the relaxation time on lipid concentration at different pH values. The analysis yielded apparent adsorption rate constants of kasAH = 9.8 X 10(6) M-1 s-1 and kasA = 1.3 X 10(6) M-1 s-1 (expressed in terms of monomeric lipid), and kasAH = 1.2 X 10(11) M-1 s-1 and kasA = 1.6 X 10(10) M-1 s-1 (expressed in terms of vesicle concentration). From the order of these rate constants it is concluded that adsorption of both species is actually diffusion-controlled. The peculiar pH dependence of the relaxation time is a consequence of the protolytic reaction in the surface regi...Continue Reading

References

Feb 1, 1969·The British Journal of Social and Clinical Psychology·R D Francis
Jul 1, 1969·Analytical Biochemistry·H Eibl, W E Lands

Related Concepts

Methyl red, sodium salt
Azo Compounds
Organic Pigments
Hydrogen-Ion Concentration
Niosomes
Phosphatidylcholines

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.