The amino acid sequence of chymodenin, a hormone-like peptide from porcine duodenum, is identical to cytochrome C-oxidase, peptide VII

Bennett, H. P. J.; Chang, Ruth; Nelbach, Lisa; Adelson, Joel W.

doi:10.1016/0167-0115(90)90086-c

Cited by 8 publications

(3 citation statements)

References 13 publications

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“…Subunit VI might be a candidate for zinc binding: in cytochrome-c oxidase from bovine heart (Biewald and Buse, 1982), rat liver and brain (Goto et al, 1989), yeast (Maarse et al, 1984) and Dictyosteliurn discoideum (Rizzuto et al, 1991) this subunit is characterized by the presence of three cysteines in invariant positions, two of which are not reactive with sulfhydryl reagents in the native enzyme (Buse et al, 1985). The version of Pan et al (1991b), however, is difficult to accept since in one of the proposed subunits (VII) all cysteines are involved in disulfide bridges (Buse et al, 1985;Bennett et al, 1990). The function and localization of the Mgz+ are not known, we have noticed, however, that its contents parallel the phosphorus contents in the Paracoccus enzyme.…”

Section: The Metal Sitesmentioning

confidence: 69%

Stoichiometry and redox behaviour of metals in cytochrome‐c oxidase

Steffens

Soulimane

Wolff

et al. 1993

European Journal of Biochemistry

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The early observation of extra copper in preparations of cytochrome-c oxidase has recently lead to a renewed interest in its stoichiometry and possible redox function. In various, pure preparations (heme A contents close to the theoretical value of 9.79 nmoVmg protein for the 13-subunit bovine enzyme) protein-related metal stoichiometries of 3 Cu, 2 Fe, 1 Zn, 1 Mg/monomer with M, 204266 were determined.Despite the presence of five potential redox metal ions, reductive and reoxidative titrations indicate the presence of only four one-electron-accepting/donating species in the ligand-free enzyme.Participation of two copper ions in a binuclear copper site acting as a one-electron acceptor may explain both the observed copper stoichiometry and the redox behaviour. The homology of the Cterminal sequence of subunit I1 with one of the copper-binding sites in nitrous-oxide reductases provides possible ligands for complexing two copper ions in a binuclear center.Cytochrome-c oxidase is a multisubunit protein localized in the inner mitochondria1 membrane of eucaryotes and the plasma membrane of many aerobic bacteria. The solubilized enzyme transfers electrons from cytochrome-c (Cyt-c) to molecular oxygen, which is thereby reduced to form water. According to the reaction equation 4Cyt-c2+ + 8H+ + 0, = 4Cyt c3+ + 4H: + 2H20 the free energy of the in-vivo-catalyzed reaction is conserved as an electrochemical proton potential by the twofold process of water formation and vectorial pumping across the membrane (H:), depleting protons (H,+) from the inner compartment. Ever since the fist description of the enzyme, experiments have been undertaken aiming at an understanding of the reaction mechanism of this important enzyme. However, nobody has yet achieved a preparation of this complex membrane protein which fulfills all criteria of purity, stoichiometry, activity and monodispersity. In addition to the doubt which this situation imposes on investigation of its reaction mechanism, this may be the reason why analysis of its threedimensional structure, either by two-dimensional or threedimensional crystallization, has so far remained inconsistent or unsuccessful.Correspondence to G. Buse, Institut fir Biochemie, RheinischWestfdische Technische Hochschule Aachen, Klinikum Pauwelsstrasse 30, W-5100 Aachen, Germany Fax: +49 241 80 88851. Abbreviations. ICP-AES, inductively coupled plasma atomicemission spectroscopy ; Pth, phenylthiohydantoin; EXAFS, extended X-ray absorption fine structure; T,max, maximal turnover number.

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Section: The Metal Sitesmentioning

confidence: 69%

Stoichiometry and redox behaviour of metals in cytochrome‐c oxidase

Steffens

Soulimane

Wolff

et al. 1993

European Journal of Biochemistry

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“…This subunit, according to its sequence and blocking group, does not belong to the membraneintercalating or membrane-penetrating chains of the complex and resides on its cytoplasmic surface (Willems, 1989). Subunit VII has recently been identified by homology to a porcine sequence (Bennett et al, 1990) to be a hormone-like peptide, which seems not to be functional for cytochrome-c oxidase but may be necessary for its assembly (LaMarche et al, 1992). It is substoichiometric in enzymes isolated after treatment with highcholate and high-salt concentrations (Planques et al, 1989 ;Weishaupt and Kadenbach, 1992).…”

Section: Discussionmentioning

confidence: 99%

Integral Cytochrome‐c Oxidase

Soulimane

Buse

1995

European Journal of Biochemistry

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A new rapid procedure for the preparation of monodispersed highly active cytochrome-c oxidase from bovine heart is described. The crucial step is the separation of cytochrome-c oxidase from cytochrome-c reductase by selective solubilization in the non-ionic detergents Triton X-1 00 or lauryl P-D-makoside. The enzyme is purified by subsequent anion-exchange chromatography. The preparation is finished within two days yielding approximately 60% of the oxidase present in mitochondria. The enzyme has a heme alprotein ratio of 9.7 +-0.5 nmol/mg, approximately equal to the theoretical value of 9.77 nmol/mg based on a molecular mass of 204.696 kDa for the protein monomer. SDSPAGE of the preparation reveals the presence of the well-known thirteen protein components. Quantitative Edman degradation of the enzyme exclusively releases the known ten N-terminal residues; three of the thirteen protein components are blocked at the N-terminus. The preparation is highly active with maximal turnover numbers of approximately 600 s-I, identical to the maximal activity found in the mitochondrial membrane under these conditions. No g = 12 signal and no adventitious copper signal are observed in the EPR spectrum. The enzyme exhibits a fast monophasic reaction with cyanide.Determination of the metal contents of the enzyme indicates the stoichiometric presence of three copper ions besides two iron, one magnesium and one zinc ion in relation to the 94 sulfur atoms of the protein monomer. Gel-filtration experiments show a monodispersed dimeric association to form a complex of approximately 500 kDa. The phosphorus content, 44 -+ 6.8 atomddimer, results from 59% cardiolipin, 23 % phosphatidylethanolamine and 18 % phosphatidylcholine, indicating a stable lipid shell, different from other previously described preparations.Crystals have been obtained from these preparations and are investigated for their suitability for Xray work.Keywords. Cytochrome-c oxidase ; integral cytochrome-c oxidase ; membrane proteins ; mitochondria ; respiratory chain.Since the first isolation of the terminal oxidase from the mitochondrial respiratory membrane (Keilin and Hartree, 1938), many attempts have been undertaken to provide suitable enzyme preparations for spectroscopic and kinetic investigations of the scalar and vectorial1 reactions catalyzed by this important metalloprotein according to the reaction equation :where H, and H, represent protons at the inner (i) and outer ( 0 ) side of the membrane. Several years ago, our group developed a preparation of the bovine heart oxidase suitable for protein chemical investigation (Steffens and Buse, 1976) from which all 13 subunits of this complex membrane protein were isolated and sequenced (Buse

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“…Peptides of that group have so far been studied in less detail; however, their number has dramatically increased in the past few years. These peptides were shown to originate from cytochrome c oxidase [14], myelin basic protein [2,15], g-globulins [4,16], serum albumin [17] and some other proteins [6,18,19], the main source of such peptides being a haemoglobin ([20±29]; for review see [3]). The present work follows the`from structure to function' approach and deals with the analysis of bovine brain extracts for individual peptide components.…”

Section: Introductionmentioning

confidence: 99%

Peptides from bovine brain: structure and biological role

et al. 1998

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Fractionation of bovine brain extracts followed by automatic Edman sequencing of individual components resulted in identification of 107 endogenous peptides formed from functional proteins (haemoglobin, myelin basic protein, cytochrome c oxidase, etc) or unknown precursors. Several of the newly identified brain peptides demonstrate different types of biological activity; some of the substances show considerable overlap with the known biologically active peptides. It is suggested that these peptides should participate in regulation of extracellular and intracellular biochemical processes. A concept of 'tissue-specific peptide pool' is formulated describing a novel system of peptidergic regulation, complementary to the conventional hormonal and neuromodulatory systems. According to that description functional proteins provide their proteolytically derived fragments for maintaining the tissue homeostasis by modulating the availability of peptide receptors to respective 'true' ligands.

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The amino acid sequence of chymodenin, a hormone-like peptide from porcine duodenum, is identical to cytochrome C-oxidase, peptide VII

Cited by 8 publications

References 13 publications

Stoichiometry and redox behaviour of metals in cytochrome‐c oxidase

Stoichiometry and redox behaviour of metals in cytochrome‐c oxidase

Integral Cytochrome‐c Oxidase

Peptides from bovine brain: structure and biological role

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