The nature of mitochondrial respiration and discrimination between membrane and pump properties.

Biochem J

C.N.R. Unit for the Study of Physiology of Mitochondria, University of Padova, Italy.

Published: September 1995

A new criterion is utilized for the interpretation of flow-force relationships in rat liver mitochondria. The criterion is based on the view that the nature of the relationship between the H+/O ratio and the membrane potential can be inferred from the relationship between ohmic-uncoupler-induced extra respiration and the membrane potential. Thus a linear relationship between extra respiration and membrane potential indicates unequivocally the independence of the H+/O ratio from the membrane potential and the leak nature of the resting respiration [Brand, Chien, and Diolez (1994) Biochem. J. 297, 27-29]. On the other hand, a non-linear relationship indicates that the H+/O ratio is dependent on the membrane potential. The experimental assessment of this relationship in the presence of an additional ohmic leak, however, is rendered difficult by both the uncoupler-induced depression of membrane potential and the limited range of dependence of the H+/O ratio on the membrane potential. We have selected conditions, i.e. incubation of mitochondria at low temperatures, where the extent of non-linearity is markedly increased. It appears that the nature of the resting respiration of mitochondria in vitro is markedly dependent on the temperature: at low temperatures the percentage of resting respiration due to membrane leak decreases and that due to intrinsic uncoupling of the proton pumps increases.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1135920PMC
http://dx.doi.org/10.1042/bj3100477DOI Listing

Publication Analysis

Top Keywords

membrane potential
28
h+/o ratio
16
ratio membrane
12
respiration membrane
12
resting respiration
12
membrane
9
extra respiration
8
nature resting
8
low temperatures
8
potential
7

Similar Publications

Outcomes for Children With Congenital Heart Disease Undergoing Ventricular Assist Device Implantation: An ACTION Registry Analysis.

J Am Coll Cardiol

December 2024

Division of Cardiology, Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.

Background: There are no contemporary reports that highlight the national outcomes for children with congenital heart disease (CHD) undergoing ventricular assist device (VAD) implantation.

Objectives: This study sought to evaluate differences in VAD outcomes for children with CHD to those with non-CHD as well as those with univentricular CHD to those with biventricular CHD.

Methods: Data for CHD and non-CHD patients from the multicenter ACTION (Advanced Cardiac Therapies Improving Outcomes Network) undergoing VAD implantation from April 2018 to February 2023 were included.

View Article and Find Full Text PDF

Pemphigus and Bullous Pemphigoid Following COVID-19 Vaccination: A Systematic Review.

Viruses

December 2024

Section of Dermatology, Department of Clinical Medicine and Surgery, University of Naples Federico II, Via Pansini 5, 80131 Napoli, Italy.

The COVID-19 pandemic has encouraged the rapid development and licensing of vaccines against SARS-CoV-2. Currently, numerous vaccines are available on a global scale and are based on different mechanisms of action, including mRNA technology, viral vectors, inactive viruses, and subunit particles. Mass vaccination conducted worldwide has highlighted the potential development of side effects, including ones with skin involvement.

View Article and Find Full Text PDF

This work presents the development of an amperometric biosensor for detecting aspartate aminotransferase (AST) activity in biological fluids using a platinum disk electrode as the working transducer. Optimal concentrations of substrates (aspartate, α-ketoglutarate) and the coenzyme (pyridoxal phosphate) were determined to ensure efficient biosensor operation. A semi-permeable poly-m-phenylenediamine membrane was applied to enhance selectivity against electroactive interferents.

View Article and Find Full Text PDF

Psoriasis is a chronic inflammatory polygenic disease with significant impacts on skin and joints, leading to substantial treatment challenges and healthcare costs. The quest for novel therapeutic avenues has recently highlighted extracellular vesicles (EVs) due to their potential as biomarkers and therapeutic agents in autoimmune diseases, including psoriasis. EVs are nano-sized, lipid membrane-bound particles secreted by cells that have emerged as promising tools for targeted drug delivery, owing to their unique structure.

View Article and Find Full Text PDF

Background: Olaparib (OLA) and regorafenib (REG) are metabolized by the CYP3A4 isoenzyme of cytochrome P450. Both drugs are also substrates and inhibitors of the membrane transporters P-glycoprotein and BCRP. Therefore, the potential concomitant use of OLA and REG may result in clinically relevant drug-drug interactions.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!