The pH‐dependent anion‐conducting channel of the mitochondrial inner membrane is potently inhibited by zinc ions

Selwyn, Michael J.; Ng, Lay Tin; Choo, Hui Lim

doi:10.1016/0014-5793(93)80311-h

Cited by 5 publications

(1 citation statement)

References 24 publications

(12 reference statements)

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“…For instance, Zn was found to bind to myoglobin and increase the oxygen affinity (oxygenation) of myoglobin (Rifkind et al, 1977). Additionally, Zn ions inhibit mitochondrial respiration (Selwyn et al, 1993;Saris and Niva, 1994); therefore, diminishing the mitochondrial oxygen consumption rate and maintaining meat color (O'Keefe and Hood, 1982). Furthermore, Zn has been reported to prevent the formation of reactive oxygen species through a mechanism that may involve protection of sulfhydryl groups against oxidation (Bettger and O'Dell, 1981), and/or displacement of redox transition metals from site-specific loci.…”

Section: Objective Colormentioning

confidence: 99%

Effect of calcium chloride, zinc chloride, and water infusion on metmyoglobin reducing activity and fresh lamb color

Bekhit

Ilian

Morton

et al. 2005

Journal of Animal Science

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Calcium chloride (CaCl2), zinc chloride (ZnCl2), or water infusions were used to investigate the biochemical factors that affect fresh lamb color, and to examine the role of metmyoglobin-reducing activity in regulating this important quality attribute. Immediately after exsanguination, lamb carcasses (n = 6 per treatment) were infused (10% of BW) with 0.3 M CaCl2, 0.05 M ZnCl2, or water via a catheter inserted into the left carotid artery. The right LM was excised at 24-h postmortem and divided into two halves. The caudal portion was cut into 2.5-cm-thick chops and displayed for 6 d under 1,076 lx of white fluorescent lighting at 2 degrees C, whereas the cranial half was vacuum-packaged and stored at 2 degrees C for 3 wk before retail display. Objective color measurements and samples for biochemical analysis were taken at 0, 1, 3, and 6 d of display. In infused carcasses, pH decline was more rapid (P < 0.05) than in untreated controls, and it was greatest for CaCl2-infused carcasses. Calcium chloride-infused carcasses had lower (P < 0.01) NAD and higher (P < 0.001) NADPH concentrations than water- and ZnCl2-infused or untreated control carcasses. The negative effects of calcium infusion on fresh lamb color, higher (P < 0.01) metmyoglobin accumulation rate, and lower (P < 0.01) L*, a*, and b* color measurements could be explained by the lower amounts of unbound water (P < 0.01), shorter sarcomere length (P < 0.01), lower NAD concentrations (P < 0.01), and higher lipid peroxidation (P < 0.01). Zinc and water-infusions produced less (P < 0.01) lipid oxidation and improved the color and color stability of fresh lamb (P < 0.001). Rate of lipid oxidation in LM chops was greater (P < 0.01) after 3 wk of vacuum-packaged storage than 24-h postmortem. Metmyoglobin-reducing activities (sarcoplasmic and myofibrillar) were decreased in response to infusion treatments (P < 0.001), and ZnCl2 infusion resulted in the lowest metmyoglobin-reducing activities (P < 0.001). A significant association between the myofibrillar metmyoglobin-reducing activity and lipid peroxidation was observed, but metmyoglobin-reducing activities were not associated with any improvement in lamb color. Strategies to increase the antioxidant levels in lamb are very important to improve lamb quality, especially during vacuum-packaging storage.

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Section: Objective Colormentioning

confidence: 99%

Effect of calcium chloride, zinc chloride, and water infusion on metmyoglobin reducing activity and fresh lamb color

Bekhit

Ilian

Morton

et al. 2005

Journal of Animal Science

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Characterization of a chloride channel reconstituted from cardiac sarcoplasmic reticulum

Townsend

Rosenberg

1995

J. Membarin Biol.

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We have characterized a voltage-sensitive chloride channel from cardiac sarcoplasmic reticulum (SR) following reconstitution of porcine heart SR into planar lipid bilayers. In 250 mM KCl, the channel had a main conductance level of 130 pS and exhibited two substrates of 61 and 154 pS. The channel was very selective for Cl- over K+ or Na+ (PK+/PCl- = 0.012 and PNa+/PCl- approximately 0.040). It was permeable to several anions and displayed the following sequence of anion permeability: SCN- > I- > NO3- approximately Br- > Cl- > F- > HCOO-. Single-channel conductance saturated with increasing Cl- concentrations (Km = 900 mM and gamma max = 488 pS). Channel activity was voltage dependent, with an open probability ranging from approximately 1.0 around 0 mV to approximately 0.5 at +80 mV. From -20 to +80 mV, channel gating was time-independent. However, at voltages below -40 mV the channel entered a long-lasting closed state. Mean open times varied with voltage, from approximately 340 msec at -20 mV to approximately 6 msec at +80 mV, whereas closed times were unaffected. The channel was not Ca(2+)-dependent. Channel activity was blocked by disulfonic stilbenes, arylaminobenzoates, zinc, and cadmium. Single-channel conductance was sensitive to trans pH, ranging from approximately 190 pS at pH 5.5 to approximately 60 pS at pH 9.0. These characteristics are different from those previously described for Cl- channels from skeletal or cardiac muscle SR.

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The mitochondrial inner membrane anion channel is inhibited by DIDS

Beavis

Davatol-Hag

1996

J Bioenerg Biomembr

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The mitochondrial inner membrane anion channel (IMAC) is a channel, identified by flux studies in intact mitochondria, which has a broad anion selectivity and is maintained closed or inactive by matrix Mg2+ and H+. We now present evidence that this channel, like many other chloride/anion channels, is reversibly blocked/inhibited by stilbene-2,2'-disulfonates. Inhibition of malonate transport approaches 100% with IC50 values of 26, 44, and 88 mu M for DIDS, H2-DIDS, and SITS respectively and Hill coefficients < or = 1. In contrast, inhibition of Cl- transport is incomplete, reaching a maximum of about 30% at pH 7.4 and 65% at pH 8.4 with an IC50 which is severalfold higher than that for malonate. The IC50 for malonate transport is decreased about 50% by pretreatment of the mitochondria with N-ethylmaleimide. Raising the assay pH from 7.4 to 8.4 increases the IC50 by about 50%, but under conditions where only the matrix pH is made alkaline the IC50 is decreased slightly. These properties and competition studies suggest that DIDS inhibits by binding to the same site as Cibacron blue 3GA. In contrast, DIDS does not appear to compete with the fluorescein derivative Erythrosin B for inhibition. These findings not only provide further evidence that IMAC may be more closely related to other "Cl-" channels than previously thought, but also suggest that other Cl- channels may be sensitive to some of the many regulators of IMAC which have been identified.

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The pH‐dependent anion‐conducting channel of the mitochondrial inner membrane is potently inhibited by zinc ions

Cited by 5 publications

References 24 publications

Effect of calcium chloride, zinc chloride, and water infusion on metmyoglobin reducing activity and fresh lamb color

Effect of calcium chloride, zinc chloride, and water infusion on metmyoglobin reducing activity and fresh lamb color

Characterization of a chloride channel reconstituted from cardiac sarcoplasmic reticulum

The mitochondrial inner membrane anion channel is inhibited by DIDS

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