What is the function of valinomycin?

Valinomycin is a potent antibiotic. It is commonly used as an agent to induce apoptosis and can also be used to calibrate potentiometric responses in membrane experiments involving potential-sensitive dyes such as di-4-ANEPPS. For Research Use Only. Not for human or animal therapeutic or diagnostic use.

Why is valinomycin a powerful antibiotic?

Valinomycin is highly selective for potassium ions over sodium ions within the cell membrane. It functions as a potassium-specific transporter and facilitates the movement of potassium ions through lipid membranes “down” the electrochemical potential gradient.

How does valinomycin affect cellular respiration?

Valinomycin produces higher steady state potassium phosphate swelling which can be reversed to give active shrinkage if mersalyl is added to block the Pi−/OH− antiporter. Respiration declines concurrently. Uncouplers accelerate the shrinkage and restore the respiration.

How does valinomycin affect ATP synthesis?

However, a lag in phosphorylation was observed when ATP synthesis was initiated by oxygen or NADH. Valinomycin caused transient uncoupling of ATP synthesis driven by respiration since it strongly inhibited ATP synthesis during the initial 100 ms but had no effect during steady state phosphorylation.

Is valinomycin an antibiotic?

Valinomycin is a depsipeptide antibiotic which selectively translocates potassium across biologic membranes. This potassium ionophore was observed to inhibit phytohemagglutinin-stimulated blastogenesis and proliferation in human lymphocytes.

What is the structure of valinomycin?

Valinomycin is a twelve-membered cyclodepsipeptide composed of three repeating D-alpha-hydroxyisovaleryl-D-valyl-L-lactoyl-L-valyl units joined in sequence. An antibiotic found in several Streptomyces strains. It has a role as an antiviral agent, an antimicrobial agent, a potassium ionophore and a bacterial metabolite.

Is valinomycin an ionophore?

What is Valinomycin? It is a polymer in ringed form, which increases the permeability of K +. It is an ionophore that is capable of transporting potassium ions through the cell membrane. This ionophore is highly selective for potassium ions over sodium ions.

What type of transport is valinomycin?

(a) Valinomycin 2.2) is a mobile carrier ionophore which catalyses the electrical uniport of Cs+, Rb+, K+ or . The ability to transport Na+ is at least 104 less than for K+. Valinomycin is a natural antibiotic from Streptomyces and is a depsipeptide, i.e. it consists of alternating hydroxy and amino acids.

How does Valinomycin affect mitochondrial electron transfer?

Accumulation of potassium inside the mitochondria, mediated by the highly specific ionophore valinomycin, promotes an increase in the volume of matrix (evidenced by swelling) and the interaction points between the two mitochondrial membranes are expected to increase.

Does Valinomycin act as an uncoupler or an inhibitor of oxidative phosphorylation?

Valinomycin acts as an uncoupler. It combines K+ to form a complex that passes through the inner mitochondrial membrane, dissipating the membrane potential. ATP synthesis decreases, which causes the rate of electron transfer to increase.

Is valinomycin a peptide?

Valinomycin is a typical example of a mobile ion carrier. It is a cyclic peptide with a lipophilic exterior and an ionic interior.

How does valinomycin affect mitochondrial electron transfer?