Optimal conditions for determination of cytochrome c oxidase activity in the rat heart

Title:

Optimal conditions for determination of cytochrome c oxidase activity in the rat heart

Creator:

Andrea Stieglerová, Zdeněk Drahota, Bohuslav Ošťádal, and Josef Houštěk

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:c848eb9c-6db6-4a82-b9ea-ac5a9a708c7e
uuid:c848eb9c-6db6-4a82-b9ea-ac5a9a708c7e
issn:0862-8408

Subject:

Fyziologie člověka a srovnávací fyziologie, cytochromy, cytochromes, rat heart, cytochrome c oxidase, lauryl maltoside, potassium phosphate, 14, and 612

Type:

article, články, model:article, and TEXT

Format:

print, bez média, and svazek

Description:

The determination of cytochrome c oxidase (COX) activity represents an important indicator for the evaluation of cell oxidative capacity. However, it has been shown repeatedly that different factors modify the rate of COX activity under various experimental conditions. The most important concern the ionic concentrations of the medium and the application of various detergents for the solubilization of mitochondrial membranes. We found the highest activity of COX in rat heart homogenates and mitochondria at 40-60 mM potassium phosphate. The rate of COX activity is dependent on the detergent/protein (P) ratio. Using n-dodecyl-b-D-maltoside (lauryl maltoside, LM) as the detergent, we obtained the highest activity at LM/P ratios of (50:100):1. By kinetic measurements of low-affinity binding sites in heart mitochondria, we found Vlim values of 4.3 and 22.2 mmol cytochrome c per min per mg P in the presence or absence of lauryl maltoside, respectively. The Km values were 16.7 mmol in the presence or absence of lauryl maltoside. Our results thus indicate that 1) the exact assessment of COX activity in heart homogenates and mitochondria requires the determination of optimum phosphate concentrations in the medium used, and 2) even small modifications of the experimental procedure may induce significant differences in the maximum values of COX activity., A. Stieglerová, Z. Drahota, B. Ošťádal, J. Houštěk., and Obsahuje bibliografii

Language:

English

Rights:

http://creativecommons.org/licenses/by-nc-sa/4.0/
policy:public

Source:

Physiological research | 2000 Volume:49 | Number:2

Harvested from:

CDK

Metadata only:

false