How azide ion/hydrazoic acid passes through biological membranes : an experimental and computational study

Lojevec Hartl, Simona (avtor), Žakelj, Simon (avtor), Sollner Dolenc, Marija (avtor), Smrkolj, Vladimir (avtor), Mavri, Janez (avtor)

Hydrazoic acid (HN$_3$) and its deprotonated form azide ion (N$_3$$^−$) (AHA) are toxic because they inhibit the cytochrome c oxidase complex IV (CoX IV) embedded in the inner mitochondrial membrane that forms part of the enzyme complexes involved in cellular respiration. Critical to its toxicity is the inhibition of CoX IV in the central nervous system and cardiovascular system. Hydrazoic acid is an ionizable species and its affinity for membranes, and the associated permeabilities, depend on the pH values of aqueous media on both sides of the membranes. In this article, we address the permeability of AHA through the biological membrane. In order to understand the affinity of the membrane for the neutral and ionized form of azide, we measured the octanol/water partition coefficients at pH values of 2.0 and 8.0, which are 2.01 and 0.00034, respectively. Using a Parallel Artificial Membrane Permeability Assay (PAMPA) experiment, we measured the effective permeability through the membrane, which is logP$_e$ − 4.97 and − 5.26 for pH values of 7.4 and pH 8.0, respectively. Experimental permeability was used to validate theoretical permeability, which was estimated by numerically solving a Smoluchowski equation for AHA diffusion through the membrane. We demonstrated that the rate of permeation through the cell membrane of 8.46·10$^4$ s$^{-1}$ is much higher than the rate of the chemical step of CoX IV inhibition by azide of 200 s$^{-1}$. The results of this study show that transport through the membrane does not represent the rate-limiting step and therefore does not control the rate of CoX IV inhibition in the mitochondria. However, the observed dynamics of azide poisoning is controlled by circulatory transport that takes place on a time scale of minutes.

• Jezik: Angleški jezik
• Ključne besede: azide ion, hydrazoic acid, octanol/water partition coefficient, effective permeability, PAMPA, diffusion, inhibition, cytochrome c oxidase complex IV
• Vrsta gradiva: Članek v reviji
• Tipologija: 1.01 - Izvirni znanstveni članek
• Organizacija: FFA - Fakulteta za farmacijo ; MF - Medicinska fakulteta
• Status publikacije: Objavljeno
• Različica publikacije: Objavljena publikacija
• Leto izida: 2023
• Št. strani: Str. 229–238
• Številčenje: Vol. 42, iss. 3
• PID: 20.500.12556/RUL-147004
• UDK: 615.4:54:615.9
• ISSN pri članku: 1875-8355
• DOI: 10.1007/s10930-023-10127-3
• COBISS.SI-ID: 155988995
• Datum objave v RUL: 17.07.2023

Gradivo je del revije

• Naslov: The protein journal
• Založnik: Springer Nature
• ISSN: 1875-8355
• COBISS.SI-ID: 527281689

Licence

• Licenca: CC BY 4.0, Creative Commons Priznanje avtorstva 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by/4.0/deed.sl
• Opis: To je standardna licenca Creative Commons, ki daje uporabnikom največ možnosti za nadaljnjo uporabo dela, pri čemer morajo navesti avtorja.

Sekundarni jezik

• Jezik: Slovenski jezik
• Ključne besede: azidni ion, hidrazojska kislina, porazdelitveni koeficient, oktanol/voda, efektivna prepustnost, PAMPA, difuzija, inhibicija, citokrom c oksidazni kompleks IV, toksini, farmacevtska kemija

Projekti

• Financer: ARRS - Agencija za raziskovalno dejavnost Republike Slovenije
• Številka projekta: P1-0012
• Naslov: Molekulske simulacije, bioinformatika in načrtovanje zdravilnih učinkovin