Quantitative resolution of succinate-cytochrome c reductase into succinate-ubiquinone and ubiquinol-cytochrome c reductases

A purified, active succinate-ubiquinone reductase was prepared from succinate-cytochrome c reductase without damage to ubiquinol-cytochrome c reductase by 1.1% Triton X-100 solubilization at pH 8.0, and calcium phosphate column chromatography in 50 mM Tris-succinate buffer, pH 8.0, containing 30 mM potassium phosphate. Succinate-ubiquinone reductase thus obtained contains ubiquinone and catalyzes thenoyltrifluoroacetone-sensitive oxidation of succinate by 2,6-dichlorophenolindophenol in the absence of exogenous mediator. Addition of ubiquinone enhanced the activity about 50%. Analytical sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the enzyme contains four polypeptides. The high molecular weight polypeptide contaminants usually observed in the Complex II preparation obtained by the reported method were absent. The active succinate-ubiquinone reductase can reconstitute with the cytochrome b-c1III complex, or Complex III to form succinate-cytochrome c reductase in the absence of exogenous ubiquinone or with the resolved ubiquinol-cytochrome c reductase in the presence of ubiquinone and phospholipids. Under the proper conditions, all the original succinate-cytochrome c reductase was obtained, indicating that the resolution caused no damage to the protein, despite the removal of phospholipids and ubiquinone from the ubiquinol-cytochrome c reductase region.

Multiple systems organ failure: VII. Reduction in plasma branched-chain amino acids--correlations with liver failure and amino acid infusion

Lower fractional concentrations of branched-chain amino acids were found in trauma-septic patients who did not survive than in those who survived (p values less than or equal to 0.046 to 0.001). A liver dysfunction scale was constructed on the basis of the levels of plasma bilirubin, albumin, SGOT, prothrombin time, and neurologic encephalopathy. Increased liver dysfunction was associated with reduced plasma fractional branched-chain amino acids for all branched-chain amino acids in both the surviving and nonsurviving patients except for valine in the nonsurviving group. This decrease was statistically significant (p less than or equal to 0.041 to 0.001) for leucine and isoleucine in the nonsurvivors and for valine in the survivors. The infusion of amino acids was associated with a decrease in the fractional concentrations in the nonsurvivors for leucine while the fractional concentrations of isoleucine in the nonsurvivors and isoleucine and valine in the survivors rose. The statistically significant changes (p less than 0.018 to 0.001) were for leucine in the nonsurvivors and isoleucine and valine in the survivors. When the liver dysfunction and amino acid infusion related changes are taken in;to account there were no significant differences in the fractional branched-chain concentrations between survivors and nonsurvivors. Liver dysfunction and low fractional branched-chain amino acids were linked in magnitude in a way that is consistent with the low branched-chain amino acids producing the liver dysfunction.

Clinical studies on the antitumor action of mecaphane

Over a period of 4 years, 241 patients with advanced cancer were treated with mecaphane alone in 11 hospitals. Effective objective responses were obtained in 100 patients (41.4%). The response was most conspicuous in chronic granulocytic leukemia, with remission in 37 of 40 patients; in Hodgkin's disease and lymphosarcoma response rates were 60% and 47.3%, respectively. Mecaphane had an analgesic action in metastatic osteolytic bone cancer, and two patients with such metastases even attained recalcification of the osteolytic destructive lesions. The common toxic manifestations of mecaphane were leukopenia (33.6%), gastrointestinal upsets (28.2%), and thrombocytopenia (12.8%). It is concluded, therefore, that mecaphane could be a good antitumor agent in clinical use. It is less expensive and can be taken orally. Further trials of this drug are recommended.

The participation of primary amino groups of succinate dehydrogenase in the formation of succinate-Q reductase

(1) Purified succinate dehydrogenase contains about 49 mol of lysine residues per mol enzyme. Titration of succinate dehydrogenase with fluorescamine indicates that half the lysyl groups are located on the surface of the protein and the other half are buried inside. (2) The reconstitutive activity and the low Km ferricyanide reductase activity of succinate dehydrogenase decreased as the extent of alkylation of amino groups by fluorescamine increased. (3) The inhibitory effects of fluorescamine on both activities are parallel and are succinate concentration dependent. (4) Alkylation of the native succinate-Q reductase by fluorescamine does not affect the enzymatic activity or alter the enzyme kinetic parameters. This indicates that the inhibitory effect of fluorescamine on succinate dehydrogenase is due to the modification of a specific amino group(s) on succinate dehydrogenase which is essential in the interaction with QPs to form succinate-Q reductase. The participation of an ionic group in the formation of succinate-Q reductase supports the idea of the involvement of ionic interaction between succinate dehydrogenase and QPs.

Multiple systems organ failure: III Contrasts in plasma amino acid profiles in septic trauma patients who subsequently survive and do not survive-effects of intravenous amino acids

The response of the plasma substrate and hormone profile of survivor and nonsurvivor septic trauma patients to varying rates of amino acid infusion (IVAA) were contrasted. When IVAA=0 levels of most plasma amino acids (except aspartate, tryptophan, cysteine, and proline) were lower in nonsurvivors. At IVAA=1 to 100, however, 11 of 20 plasma amino acids were significantly (p less than or equal to 0.05) higher in nonsurvivors: only glutamate was significantly lower (p less than or equal to 0.001) and valine, isoleucine, and arginine on average lower. At IVAA less than or equal to 101 to 200, only alanine, methionine, tyrosine, and phenylalanine were significantly (p less than or equal to 0.005) higher in nonsurvivors; isoleucine was significantly (p less than or equal to 0.02) lower. The sharp increase in methionine and decrease in tryptophan in nonsurvivors with IVAA was particularly marked. Polynomial regression analysis showed that urea increased significantly with IVAA in both patient groups, while free fatty acids and cortisol decreased only in nonsurvivors. Insulin increased with IVAA only in survivors, glucagon only in nonsurvivors. Triglycerides, glycerol, acetoacetate, beta OH butyrate, and glucose appeared to show no significant response to IVAA in either patient group. The data are consistent with increased peripheral protein catabolism and branched-chain amino acid oxidation in association with decreased tissue uptake of conventional energetic fuels. These results may be interpreted to be consistent with an impairment of mitochondrial translocase systems.

Multiple systems organ failure: II. The effect of infusion of amino acids and glucose

Amino acids and dextrose infusion were given for short periods of time to a young man whose basal state is characterized in the previous paper in this series, and their effects were documented in terms of plasma concentrations and splanchnic extraction. The basal state measurements show in the acute trauma state and its subsequent starvation state a largely balanced splanchnic extraction of amino acids but at a decreasing rate. Amino acid (FreAmine) infusion at low rates on this background produced a large increase in extraction of a largely balanced mixture of amino acids but a minimal change in glucose release. The septic state is characterized in both the basal and amino acid infusion state by splanchnic extraction of an unbalanced mixture of amino acids which is deficient in branched-chain amino acids and in relative excess of glucogenic amino acids with increased glucose release and increased utilization of amino acids for gluconeogenesis. In early sepsis this state can largely be repaired by exogenous amino acid infusion but in late sepsis can only be partially repaired. The data suggest that the patient in late sepsis should have a branched-chain rich amino acid mixture and that the hepatic failure of sepsis is strongly associated with peripheral release of an unbalanced mixture of amino acids secondary to enhanced branched-chain catabolism. Infused glucose produces a large increase in the plasma glucose but also improves the balance of the splanchnic amino acids extracted. The statistical validity of the preceding statements are examined in detail in the manuscript.

Structural role of phospholipids in ubiquinol-cytochrome c reductase

The role of phospholipids in ubiquinol-cytochrome c reductase has been studied by the following methods: (1) removal and restoration of phospholipids, (2) circular dichroism measurements, and (3) phospholipase A2 treatment. Over 90% of the phospholipids in the cytochrome b--c1 III complex (a highly purified ubiquinol-cytochrome c reductase) can be removed by repeated precipitation with ammonium sulfate in the presence of 0.5% sodium cholate. The delipidated enzyme complex is inactive. Full restoration of enzymatic activity can only be achieved with a freshly prepared delipidated enzyme complex, made in the presence of 20% glycerol. As the age of the delipidated enzyme increased, the amount of activity restored decreased and the incubation time required to reach maximal activity increased. Removal of phospholipids from the cytochrome b--c1 III complex resulted in an immediate decrease of approximately 15% in molar ellipticities in both the far-UV and the Soret regions. A further decrease in ellipticities was observed upon incubation of the delipidated enzyme at 0 degrees C in 50 mM phosphate buffer, pH 7.4. Replenishing phospholipids to the delipidated enzyme complex restored enzymatic activity and the molar ellipticity in both regions. The absolute requirement for phospholipids in the cytochrome b--c1 III complex was also demonstrated by treatment of the enzyme with purified phospholipase A2. The inactivation of the cytochrome b--c1 III complex by phospholipase A2 was not prevented by the presence of excess exogenous ubiquinone but was prevented by the presence of ethylenediaminetetracetic acid (EDTA). The enzymatic activity of the phospholipase A2 treated complex is fully restorable upon the addition of EDTA and phospholipids.

Resolution and reconstitution of succinate-cytochrome c reductase: preparations and properties of high purity succinate dehydrogenase and ubiquinol-cytochrome c reductase

An improved method was developed to sequentially fractionate succinate-cytochrome c reductase into three reconstitutive active enzyme systems with good yield: pure succinate dehydrogenase, ubiquinone-binding protein fraction and a highly purified ubiquinol-cytochrome c reductase (cytochrome b-c1 III complex). An extensively dialyzed succinate-cytochrome c reductase was first separated into a succinae dehydrogenase fraction and the cytochrome b-c1 complex by alkali treatment. The resulting succinate dehydrogenase fraction was further purified to homogeneity by the treatment of butanol, calcium phosphate gel adsorption and ammonium sulfate fractionation under anaerobic condition in the presence of succinate and dithiothreitol. The cytochrome b-c1 complex was separated into chtochrome b-c1 III complex and ubiquinone-binding protein fractions by careful ammonium acetate fractionation in the presence of deoxycholate. The purified succinate dehydrogenase contained only two polypeptides with molecular weights of 70 000 anbd 27 000 as revealed by the sodium dodecyl sulfate polyacrylamide gel electrophoretic pattern. The enzyme has the reconstitutive activity and a low Km ferricyanide reductase activity of 85 mumol succinate oxidized per min per mg protein at 38 degrees C. Chemical composition analysis of cytochrome b-c1 III complex showed that the preparation was completely free of contamination of succinate dehydrogenase and ubiquinone-binding protein and was 30% more pure than the available preparation. When these three components were mixed in a proper ratio, a thenoyltrifluoroacetone- and antimycin A-sensitive succinate-cytochrome c reductase was reconstituted.

Biochemical parameters of normal rabbit serum

An attempt was made to establish the normal range of 27 different parameters in the serum of 45 healthy, purebred, New Zealand White rabbits (3-5 kg). The reproducibility of the results was acceptable. Sensitive isoenzyme patterns (LDH, CK) could change, however, significantly if different methods were used in the bleeding procedure. Isoenzyme patterns (LDH and CK) of rabbit sera were different from that of human sera. All obtained results were compared with earlier data sporadically published in literature on rabbits.

Amino acid sequence of subunit V of bovine heart cytochrome oxidase, the heme alpha-containing subunit

The complete amino acid sequence of the heme alpha-containing subunit V of bovine heart cytochrome oxidase was determined to be: H2N-Ser-His-Gly-Ser-His-Glu-Thr-Asp-Glu-Glu-Phe-Asp-Ala-Arg-Trp-Val-Thr-Tyr-Phe-Asn-Lys-Pro-Asp-Ile-Asp-Ala-Trp-Glu-Leu-Arg-Lys-Gly-Met-Asn-Thr-Leu-Val-Gly-Tyr-Asp-Leu-Val-Pro-Glu-Pro-Lys-Ile-Ile-Asp-Ala-Ala-Leu-Arg-Ala-Cys-Arg-Arg-Leu-Asn-Asp-Phe-Ala-Ser-Ala-Val-Arg-Ile-Leu-Glu-Val-Val-Lys-Asp-Lys-Ala-Gly-Pro-His-Lys-Glu-Ile-Tyr-Pro-Tyr-Val-Ile-Gln-Glu-Leu-Arg-Pro-Thr-Leu-Asn-Glu-Leu-Gly-Ile-Ser-Thr-Pro-Glu-Glu-Leu-Gly-Leu-Asp-Lys-Val-COOH. The subunit V is a single polypeptide which consists of 109 amino acid residues. The protein contains 48.6% hydrophobic residues and 34.0% hydrophilic residues and it is an acidic protein having a net charge of -3 at neutral pH. The molecular weight of subunit V was calculated to be 12,436 and that for the heme alpha-containing polypeptide was 13,295.

Rapid determination of quinidine in human plasma by high-performance liquid chromatography

A sensitive and specific method for the determination of quinidine in plasma is described. Quinidine is extracted with chloroform, the extract is evaporated and reconstituted with methanol and the methanol extract is analyzed by high-performance liquid chromatography using a silica gel column. The recovery of quinidine from plasma varied between 93.0 to 100%. Quinidine levels as low as 12 ng/ml can be detected by this method.

The indispensability of phospholipid and ubiquinone in mitochondrial electron transfer from succinate to cytochrome c

The indispensability of phospholipid and ubiquinone (Q) in mitochondrial electron transfer was studied by depleting phospholipid and Q in succinate-cytochrome c reductase and then replenishing the depleted enzyme. More than 90% of phospholipid and Q was removed by repeated ammonium sulfate-cholate fractionation. The depleted succinate-cytochrome c reductase showed no enzymatic activity for succinate leads to c or QH2 leads to c and yet retained most of the succinate leads to Q activity. All enzymatic activity was restored upon the addition of Q and phospholipid. Restoration required the addition of Q prior to the addition of phospholipid. Reversing the addition sequence or addition of a mixture of phospholipid and Q resulted only in a small restoration of activities. The conditions for restoration are given in detail. Removal of phospholipid from succinate-cytochrome c reductase resulted in reduction of cytochrome c1 in the absence of exogenous electron donor. Replenishing the preparation with phospholipid brought about the reoxidation of cytochrome c1 in the absence of electron acceptor or oxygen.

Identification of subunits of bovine heart cytochrome oxidase

Purified lipid-depleted cytochrome oxidase, at purity of 12--14 nmol heme a per mg protein, has been shown to contain seven non-identical subunits in the ratio of unity. Their molucular weights on polyacrylamide gel are, in thousands, 40, 21, 14.8, 13.5, 11.6, 9.5, and 7.6 from gel electrophoresis after dissociation in sodium dodecyl sulfate and beta-mercaptoethanol. The molar ratio is determined by the amino acid composition of each subunit obtained from direct hydrolysis of the stained polyacrylamide gel slices. The amino acid composition of the isolated subunits I and II determined by regular hydrolysis method is found practically the same as that from direct hydrolysis of gel slices. The heme-associated polypeptides are identified with subunits of molecular weights of 40.10(3) and 11.6.10(3). One of the two coppers associated with the polypeptide of molecular weight of 21 000. The second copper may be associated with heme in the subunit of 40.10(3). Evidence of the existence of interpolypeptide disulfide linkages is presented.

Subunit structure of the reconstitutively active cytochrome b-c1 complex. Determination of amino acids and molar distribution of subunit fractions from gel electrophoresis

A quantitative method has been developed to analyze the amino acid composition of protein subunits directly from the Coomassie Blue-stained band of polyacrylamide gel columns after electrophoresis. It is an improved method originally reported by Houston (Houston, L. L. (1971) Anal. Biochem. 44, 81--88). The results obtained can be thus used for the calculation of the molar ratios of subunit components of protein. The manipulation of the method and computation of the results are illustrated by a very complicated lipoprotein complex. The subunit molar ratios of the reconstitutively active cytochrome b-c1 complex were determined to be 2, 2, 2, 3, 2, 2, and 5 among the seven bands of the corresponding molecular weights of 53 000, 50 000, 37 000, 30 000, 28 000, 17 000, and 15 000, from gel electrophoretic columns. The amino acid composition of each subunit fraction determined directly from hydrolysis of gel was comparable with that obtained by actual isolation of each subunit.

X-ray diffraction of actively shortening muscle

Low angle x-ray diffraction patterns were obtained from resting and activated frog sartorius muscles by means of a position-sensitive detector. Although the intensity ratio I10/I11 decreased many-fold upon activation, it was nearly the same during isometric and isotonic contraction. Thus, motion has a much smaller effect on the low order equatorial pattern than the transition from rest to activity. Analysis of the 10 and 11 reflections separately showed that I10 and I11 change reciprocally upon activation, and that they both increase by a small amount in the transition from isometric to isotonic contraction. If the intensity ratio can be taken as a measure of cross-bridge number, the results provide evidence that the drop in force in an actively shortening muscle is due primarily to the influence of motion on the configuration, rather than the number, of cross-bridges.

Photoreduction of cytochrome c1

1. Ferricytochrome c1 solution was reduced completely between pH 7 and 10 by illumination under anaerobic conditions. Photoreduction was not affected by the ionic strength of the medium. However, it did not take place at pH lower than 6 or higher than 10, or in the presence of p-hydroxymercuric benzoate. The ferricyanide-reoxidized photoreduced c1 was not further reduced upon illumination. The reductant was most probably a specific sulfhydryl group in the subunit containing the heme of the cytochrome since this subunit contained one less p-HMB-titratable group in the photoreduced sample than in the untreated preparation. 2. The photoreduced cytochrome c1 showed the same spectra as the native cytochrome, and was not reactive with carbon monoxide. The equilibrium constant of the reaction c12+ + c3+ equilibrium c13+ + c2+ for the photoreduced c1 was found to be slightly lower (Keq = 2.6) than that for the native c1 (Keq = 3.5). The antimycin A-sensitive electron acceptor activity of ferricyanide-reoxidized photoreduced c13+ catalyzed by succinate-cytochrome c reductase was about 80% of that of the native c1. 3. A somewhat simplified method for isolation of cytochrome c1 was developed. Anaerobic ammonium sulfate fractionation and calcium phosphate gel chromatography were still used in order to achieve the purity level of about 25 nmol of heme/mg of protein. The cytochrome c1 prepared by this procedure showed the same properties tested as that by the beta-mercaptoethanol method (Yu, C.A., Yu, L., and King, T.E. (1972) J. Biol. Chem. 247, 1012-1019).

Studies on cytochrome oxidase. Interactions of the cytochrome oxidase protein with phospholipids and cytochrome c

1. By the application of the principle of the sequential fragmentation of the respiratory chain, a simple-method has been developed for the isolation of phospholipid-depleted and phospholipid-rich cytochrome oxidase preparations. 2. The phospholip-rich oxidase contains about 20% lipid, including mainly phosphatidylethanolamine, phosphatidylcholine, and cardiolipin. Its enzymic activity is not stimulated by an external lipid such as asolectin. 3. The phospholipid-depleted oxidase contains less than 0.1% lipid. It is enzymically inactive in catalyzing the oxidation of reduced cytochrome c by molecular oxygen. This activity can be fully restored by asolectin; and partially restored (approximately 75%) by purified phospholipids individually or in combination. The activity can be partially restored also by phospholipid mixtures isolated from mitochondria, from the oxidase itself, and from related preparations. Among the detergents tested only Emasol-1130 and Tween 80 show some stimulatory activity. 4. The phospholipid-depleted oxidase binds with cytochrome c evidently by "protein-protein" interactions as does the phospholipid-rich or the phospholipid-replenished oxidase to form a complex with the ratio of cytochrome c to heme a of unity. The complex prepared from phospholipid-depleted cytochrome oxidase exhibits a characteristic Soret absorption maximum at 415 nm in the difference spectrum of the carbon monoxide-reacted reduced form minus the reduced form. This 415-nm maximum is abolished by the replenishment of the complex with a phospholipid or by the dissociation of the complex in cholate or in a medium of high ionic strength. When ascorbate is used as an electron donor, the complex prepared from phospholipid-depleted cytochrome oxidase does not cause the reduction of cytochrome a3 which is in dramatic contrast to the complex from the phospholipid-rich or the phospholipid-replenished oxidase. However, dithionite reduces cytochrome a3 in all of the preparations of the cytochrome c-cytochrome oxidase complex. These facts suggest that the action of phospholipid on the electron transfer in cytochrome oxidase may be at the step between cytochromes a and a3. This conclusion is substantiated by preliminary kinetic results that the electron transfer from cytochrome a to a3 is much slower in the phospholipid-depleted than in phospholipid-rich or phospholipid-replenished oxidase. On the basis of the cytochrome c content, the enzymic activity has been found to be about 10 times higher in the system with the complex (in the presence of the replenishedhe external medium unless energy is provided, and that

A trypsin-resistant heme peptide from cardiac cytochrome c1

A tryptic resistant heme peptide has been prepared and purified from cardiac cytochrome c1. This purified peptide is not further hydrolyzed by reactions of other proteolytic enzymes, such as pronase. The peptide contains 2 residues each of serine, cysteine and valine, and 1 residue each of alanine, methionine, tyrosine, histidine, arginine, proline, glutamic acid (glutamine) and aspartic acid. The intensity of the absorption spectrum of the peptide has been found to be dependent upon, but the positions of the absorption maxima do not vary with, concentration. The heme peptide does not show multiple splitting of absorption peaks at liquid N2 temperatures as does the intact cytochrome C1. However, cyanide rapidly reacts with the peptide and causes significant spectral changes. CD spectra of the peptide exhibit a typical profile of a non-structured heme peptide with positive CD bands in the Soret region and around 250 nm, and a broad negative extreme of 320-360 nm. The similarities and differences between the tryptic resistant heme peptides from cytochromes c1 and c have been compared.

Chemical and physical characteristics of the deoxycholate-soluble and magnesium-reaggregated membrane nicotinamide adenine dinucleotide (reduced form) oxidase of Bacillus megaterium

The inactive components of the nicotinamide adenine dinucleotide (reduced form) (NADH) oxidase present in the 0.4% deoxycholate-soluble fraction obtained from Bacillus megaterium KM membranes were reaggregated into active NADH oxidase by dilution in the presence of Mg(2+). The reaggregated oxidase was different from the original membrane with respect to sedimentation behavior in a sucrose gradient and morphological appearance. The deoxycholate-insoluble portion of the membrane had membrane-like structure whereas the reaggregated oxidase appeared to be a filamentous aggregate of small particles. The reaggregated oxidase and the deoxycholate-insoluble membrane residue were similar to the original membrane with respect to total protein and total lipid content. The inactive components of the NADH oxidase system exist in deoxycholate as two molecular species which were separable by sucrose density gradient centrifugation or gel filtration in deoxycholate-containing solutions. Both components and dilution in the presence of Mg(2+) were necessary for restoration of oxidase activity. The smaller-molecular-weight component contained all of the NADH-2,6-dichlorophenolindophenol oxidoreductase activity of the original membrane.

Separation of the primary dehydrogenase from the cytochromes of the nicotinamide adenine dinucleotide (reduced form) oxidase of Bacillus megaterium

A selective extraction procedure was developed for sequentially extracting a fraction containing the primary dehydrogenase and a fraction containing the cytochromes of the nicotinamide adenine dinucleotide (reduced form) (NADH) oxidase of Bacillus megaterium KM membranes. The primary dehydrogenase (NADH-2,6-dichlorophenolindophenol oxidoreductase) activity was extracted from sonically treated membranes with 0.4% sodium deoxycholate for 30 min at 4 C. The insoluble residue was extracted with 0.4% sodium deoxycholate in 1 m KCl for 30 min at 25 C. A combination of the two extracts and dilution in Mg(2+) gave good recovery of the original membrane NADH oxidase activity. The primary dehydrogenase fraction contained 41% of the membrane protein, no cytochromes, flavine adenine dinucleotide as the sole acid-extractable flavine, and most of the membrane ribonucleic acid (RNA). The cytochrome-containing fraction had 16% of the membrane protein, 61% of the membrane cytochrome with the same relative amounts of cytochromes a and b as the original membrane, no acid-extractable flavine, little RNA, and no oxidoreductase activity. The oxidoreductase fraction remained soluble after removal of deoxycholate whereas the cytochrome fraction became insoluble after removal of deoxycholate-KCl, but the precipitated fraction could be redissolved in 0.4% sodium deoxycholate. Treatment of both fractions with ribonuclease to destroy all of the RNA present did not affect the ability of the fractions to recombine into a functional oxidase unit. Treatment of either fraction with phospholipase A prevented restoration of a functional oxidase when the oxidoreductase and cytochrome fractions were treated in solution, but no affect on restoration of oxidase was observed when the phospholipase A treatment was carried out with the soluble oxidoreductase fraction and the insoluble cytochrome fraction.