Thioredoxin-dependent Hydroperoxide Peroxidase Activity of Bacterioferritin Comigratory Protein (BCP) as a New Member of the Thiol-specific Antioxidant Protein (TSA)/Alkyl Hydroperoxide Peroxidase C (AhpC) Family

Escherichia coli bacterioferritin comigratory protein (BCP), a putative bacterial member of the TSA/AhpC family, was characterized as a thiol peroxidase. BCP showed a thioredoxin-dependent thiol peroxidase activity. BCP preferentially reduced linoleic acid hydroperoxide rather than H2O2 and t-butyl hydroperoxide with the use of thioredoxin as an in vivo immediate electron donor. The value of V max/K mof BCP for linoleic acid hydroperoxide was calculated to be 5-fold higher than that for H2O2, implying that BCP has a selective capability to reduce linoleic acid hydroperoxide. Replacement of Cys-45 with serine resulted in the complete loss of thiol peroxidase activity, suggesting that BCP is a new bacterial member of TSA/AhpC family having a conserved cysteine as the primary site of catalysis. BCP exists as a monomer, and its functional Cys-45 appeared to exist as cysteine sulfenic acid. The expression level of BCP gradually elevated during exponential growth until mid-log phase growth, beyond which the expression level was decreased. BCP was induced 3-fold by the oxidative stress given by changing the growth conditions from the anaerobic to aerobic culture. Bcp null mutant grew more slowly than its wild type in aerobic culture and showed the hypersensitivity toward various oxidants such as H2O2, t-butyl hydroperoxide, and linoleic acid hydroperoxide. The peroxide hypersensitivity of the null mutant could be complemented by the expression of bcp gene. Taken together, these data suggest that BCP is a new member of thioredoxin-dependent TSA/AhpC family, acting as a general hydroperoxide peroxidase. Escherichia coli bacterioferritin comigratory protein (BCP), a putative bacterial member of the TSA/AhpC family, was characterized as a thiol peroxidase. BCP showed a thioredoxin-dependent thiol peroxidase activity. BCP preferentially reduced linoleic acid hydroperoxide rather than H2O2 and t-butyl hydroperoxide with the use of thioredoxin as an in vivo immediate electron donor. The value of V max/K mof BCP for linoleic acid hydroperoxide was calculated to be 5-fold higher than that for H2O2, implying that BCP has a selective capability to reduce linoleic acid hydroperoxide. Replacement of Cys-45 with serine resulted in the complete loss of thiol peroxidase activity, suggesting that BCP is a new bacterial member of TSA/AhpC family having a conserved cysteine as the primary site of catalysis. BCP exists as a monomer, and its functional Cys-45 appeared to exist as cysteine sulfenic acid. The expression level of BCP gradually elevated during exponential growth until mid-log phase growth, beyond which the expression level was decreased. BCP was induced 3-fold by the oxidative stress given by changing the growth conditions from the anaerobic to aerobic culture. Bcp null mutant grew more slowly than its wild type in aerobic culture and showed the hypersensitivity toward various oxidants such as H2O2, t-butyl hydroperoxide, and linoleic acid hydroperoxide. The peroxide hypersensitivity of the null mutant could be complemented by the expression of bcp gene. Taken together, these data suggest that BCP is a new member of thioredoxin-dependent TSA/AhpC family, acting as a general hydroperoxide peroxidase. reactive oxygen species bacterioferritin comigratory protein thiol specific antioxidant protein alkyl hydroperoxide peroxidase C dithiothreitol metal-catalyzed oxidation thioredoxin thioredoxin reductase N-ethylmaleimide 7-chloro-4-nitrobenzo-2-oxo-1,3-diazol reduced glutathione polyacrylamide gel electrophoresis glutamine synthetase tertiary butyl hydroperoxide polymerase chain reaction dithiothreitol ferrous ion oxidation in the presence of xylenol orange Reactive oxygen species (ROS)1 are potent oxidants capable of damaging all cellular constituents. To protect against the toxicity of ROS, aerobic organisms are equipped with an array of defense mechanism (1.Halliwell B. Gutterridge J.M.C. Free Radical in Biology and Medicine. 2nd Ed. Clarendon Press, Oxford1989Google Scholar). In mammals, glutathione peroxidase acts a general hydroperoxide to reduce H2O2 and alkyl hydroperoxides including fatty acid hydroperoxide (1.Halliwell B. Gutterridge J.M.C. Free Radical in Biology and Medicine. 2nd Ed. Clarendon Press, Oxford1989Google Scholar, 2.Michiels C. Raes M. Taussaint O. Remacle J. Free Radic. Biol. Med. 1994; 17: 235-248Crossref PubMed Scopus (1044) Google Scholar). The alkyl hydroperoxide reductase (AhpC)/TSA family is a new type of peroxidase that has a conserved cysteine as the primary site of catalysis instead of the selenocysteine of glutathione peroxidase. The new type of peroxidase that has been discovered from prokaryotes to eukaryotes (3.Chae H.Z. Rhee S.G. Biofactors. 1994; 4: 177-180PubMed Google Scholar,4.Chae H.Z. Robison K. Poole L.B. Church G. Storz G. Rhee S.G. Proc. Natl. Acad. Sci. U. S. A. 1994; 91: 7017-7021Crossref PubMed Scopus (706) Google Scholar) reduces hydroperoxides with the use of thioredoxin and other thiol-containing reducing agents (5.Cha M.K. Kim I.H. Biochem. Biophys. Res. Commun. 1995; 217: 900-907Crossref PubMed Scopus (63) Google Scholar, 6.Chae H.Z. Chung S.J. Rhee S.G. J. Biol. Chem. 1994; 269: 27670-27678Abstract Full Text PDF PubMed Google Scholar, 7.Kwon S.J. Park J.W. Choi W.K. Kim I.H. Kim K. Biochem. Biophys. Res. Commun. 1994; 201: 8-15Crossref PubMed Scopus (100) Google Scholar). Only two bacterial member of the new peroxidase family have been reported, although at least five types of thiol peroxidase exist in eukaryotic cell. In Escherichia coli, AhpC was reported to preferentially reduce alkyl hydroperoxide with electrons provided by either NADH or NADPH via the AhpF52 (8.Jacobson F.S. Morgan R.W. Christman M.F. Ames B.N. J. Biol. Chem. 1989; 264: 1488-1496Abstract Full Text PDF PubMed Google Scholar). Recently, we reported a novel type of peroxidase, p20, that acts as an antioxidant to remove peroxides such as H2O2 and alkyl hydroperoxide in the periplasmic space of E. coli (9.Cha M.K. Kim H.K. Kim I.H. J. Biol. Chem. 1995; 270: 28635-28641Abstract Full Text Full Text PDF PubMed Scopus (126) Google Scholar). The similarity of primary structure between bacterioferritin comigratory protein (BCP) and the TSA/AhpC family suggested that BCP could be another new member of the family. However, the function of BCP has not yet been clarified despite of the wide distribution of BCP in most pathogenic bacteria including Haemophilus influenzae,Helicobactor pylori, and Mycobacterium tuberculosis as p20. In this paper, we first showed that BCP is a new bacterial member of the TSA/AhpC family, acting as a general hydroperoxide peroxidase. The DNA sequence corresponding to BCP was obtained by the polymerase chain reaction (PCR) from E. coli genomic DNA using the forward primer (5′-G GAA TTC CAT ATG AAT CCA CTG AAA GCC GGT GAT ATC-3′) containing an NdeI (underlined) site and the initiation codon (boldface) and the reverse primer (5′-CGC GGA TCC TCA GGC GTG TTC TTT CAG CCA GTT CAG-3′) containing the BamHI site (underlined) and the stop codon (boldface). The amplified products were purified and digested withNdeI/BamHI. The digested fragments were subcloned into the T7 expression vector, pT7–7 digested withNdeI/BamHI, and the resulting plasmid was used to transform E. coli strain BL21 (DE3). Three mutant proteins, C45S, C50S, and C99S, in which Cys-45, Cys-50, and Cys-99 were individually replace by serine, were generated by the standard PCR-mediated site-directed mutagenesis with complementary primers containing a 1-base pair mismatch, which converts the codon for cysteine to one for serine. The mutated PCR products were ligated into pT7–7 digested with NdeI/BamHI. Transformed cells were cultured at 37 °C overnight in LB medium supplemented with ampicillin (100 μg/ml) and then transferred to fresh medium to the ratio of 1 to 200. When the optical density of the culture at 600 nm reached 0.4, isopropyl-1-thio-β-d-galactopyranoside was added to a final concentration of 0.5 mm. After induction for 3 h, cells were harvested by centrifugation and stored at −70 °C until use. Frozen cells were suspended in 50 mm Tris-HCl (pH 7.6) containing 2 mm phenylmethyl sulfonyl fluoride and 1 mm EDTA and disrupted by sonication. The supernatants clarified by centrifugation were loaded to Q-Sepharose column that had been equilibrated with 50 mm Tris-HCl (pH 7.6). Proteins were eluted with a linear gradient of NaCl from 0 to 0.5 mover 100 min at a flow rate of 2 ml/min. The fractions corresponding to the peak of BCP were pooled and dialyzed against 50 mmsodium acetate (pH 5.0). After dialysis, samples were applied to SP-Sepharose column that had been equilibrated with 50 mmsodium acetate (pH 5.0). The samples eluted with a linear gradient of NaCl were dialyzed against 10 mm Tris-HCl (pH 7.4) and stored at −70 °C. The antioxidant activity was determined by measuring the activity to protect the inactivation of E. coli glutamine synthetase (GS) by a thiol metal-catalyzed oxidation system (DTT/Fe3+/O2) (thiol MCO system) (10.Stadtman E.R. Oliver C.N. J. Biol. Chem. 1991; 266: 2005-2008Abstract Full Text PDF PubMed Google Scholar) as described previously (11.Kim K. Kim I.H. Lee K.Y. Rhee S.G. Stadtman E.R. J. Biol. Chem. 1988; 263: 4704-4711Abstract Full Text PDF PubMed Google Scholar). Instead of DTT, ascorbate was included as a non-thiol-reducing equivalent (non-thiol MCO system). The 30-μl reaction mixture containing 100 mm Hepes-NaOH (pH 7.0), 1.0 μg of GS, 3 μm FeCl3, various concentration of BCP and either 10 mm DTT or 10 mm ascorbate, was incubated at 37 °C, and then 0.5 ml of γ-glutamyltransferase assay mixture was added. After incubation at 37 °C for 10 min, the remaining activity of GS was determined by measuring the absorbance at 540 nm. To determine the thioredoxin (Trx)-linked antioxidant activity of BCP, the GS activity was measured in the reaction mixture containing 100 mm HEPES-NaOH (pH 7.0), 1.0 μg of GS, 3 μm FeCl3, various concentrations of BCP, 10 mm ascorbate, 10.8 μm Trx, 3.9 μm thioredoxin reductase (TR), and 1 mmNADPH. A peroxidase reaction was performed in a 400-μl reaction mixture containing 50 mm Hepes-NaOH (pH 7.0), 0.8 μmTrx, 0.3 μm TR, 0.26 mm NADPH, various concentrations of BCP, and 0.1 mmH2O2 or 0.1 mm t-butyl hydroperoxide (t-BOOH) or 0.04 mm linoleic acid hydroperoxide at room temperature. Linoleic acid hydroperoxide was generated by incubating 0.1 mm linoleic acid with 10 μg/ml soybean lipoxygenase in 50 mm Hepes-NaOH (pH 7.0) at room temperature for 10 min (12.Roveri A. Maiorino M. Ursini F. Methods Enzymol. 1994; 233: 202-212Crossref PubMed Scopus (151) Google Scholar). The concentration of linoleic acid hydroperoxide was determined spectrophotometrically (ε234= 25,000 m−1 cm−1). At the appropriate time, 20 μl of reaction mixture was added to 1 ml of FOX1 reagent and then incubated at room temperature for 30 min, at which time color development was virtually complete (13.Wolff S.P. Methods Enzymol. 1994; 233: 182-189Crossref Scopus (1085) Google Scholar). The remaining amount of peroxide was monitored by measuring the absorbance at 560 nm. The peroxidase activity of BCP linked to NADPH oxidation via Trx system was monitored as the decrease of A 340 in a 400-μl reaction mixture containing 50 mm Hepes-NaOH (pH 7.0), 0.8 μm Trx, 0.3 μm TR, 0.2 mm NADPH, and various concentrations of either H2O2 or t-butyl hydroperoxide. BCP was preincubated in the absence or presence of 2.5 mm DTT at 30 °C for 30 min, and then chemical modification was carried out in a 100-μl reaction mixture containing 50 mm Tris-HCl (pH 8.0), 1.2 mg BCP, and 20 mmNEM or iodoacetamide at 30 °C for overnight as described previously (14.Lundblad R.L. Noyes C.M. Chemical Reagents for Protein Modification. 1. CRC Press, Inc., Boca Raton, FL1984: 55-93Google Scholar). For the modification of BCP with NBD-Cl, 75 nmol of BCP was reacted with 450 nmol of NBD-Cl in 50 mm potassium with 0.1 mm EDTA at at 30 °C for 2 as described previously Poole L.B. PubMed Scopus Google Scholar). The reaction were dialyzed against 10 mm (pH 7.0) at °C. The BCP protein was by mm (pH containing 3 The resulting protein was with and the was suspended in 100 mm Tris-HCl and the protein was digested with for 3 at 30 °C. The with fresh was carried out The were by a phase column mm with a linear gradient of in acid min at a 1 flow The were using a array and a To the BCP the sequence of the initiation codon of the BCP was by The forward primer GAA TTC AAA CAG GAA an site and the reverse primer (5′-CGC GGA TCC CCA TCC TCA a site PCR products were subcloned into and the resulting plasmid was used for E. coli Transformed cells were cultured or in LB medium containing 50 μg/ml ampicillin at 37 °C. At mid-log phase or culture time, the optical density at 600 nm was and cells were The cells were in μl of 10 mm 1 mm to 7.0) and were with μl of and μl of by for 10 The were by μl of μm After incubation at 30 °C for 10 min, the were by the of μl of 1 The was by and then activity was measured in of the of absorbance at nm of the The activity was as A in A and for Escherichia coli and Press, Scholar). The null were generated by the To the containing the bcp and its PCR was carried out using the forward primer TTC AAA CAG GAA containing site and the reverse primer TCC TCA GGC GTG TTC TTT CAG CCA GTT containing the BamHI site and then the PCR was into site of The resulting plasmid In the of the PCR amplified using the forward primer TTC CAT ATG CAG GGC GAA GAT containing a NdeI site and the reverse primer TTT CCA GGT CCA containing a site was into site of The resulting plasmid was as To the into the bcp PCR was performed using the forward primer GAT containing an site and the reverse primer GAA containing site For the the reverse primer TTT CCA GGT CCA containing site was PCR was into site of and site of The resulting were used as a in PCR to and pair DNA fragments containing the bcp and disrupted by of PCR products were used for E. coli strain and cells were The acid sequence the BCP is The sequence the conserved the BCP suggested that the BCP be a new member of the TSA/AhpC family. The BCP is in most bacteria pylori, and M. tuberculosis To E. coli BCP, a putative bacterial member of was BCP was purified from the E. coli BCP The of the purified BCP was 2 The BCP was at the corresponding to that of of the presence or absence of suggested that E. coli BCP exists as is in an of BCP of the from E. reducing gel and and from the of E. coli BCP 2 and and AhpC 1 and reducing 1 and or and The of AhpC was as In the presence of a thiol-containing electron such as DTT, the TSA/AhpC family has the antioxidant activity of the inactivation of GS by the MCO which is of DTT, and thiol MCO system) (1.Halliwell B. Gutterridge J.M.C. Free Radical in Biology and Medicine. 2nd Ed. Clarendon Press, Oxford1989Google Scholar). has been that the of a thiol-containing electron with a electron such as ascorbate MCO system) resulted in the complete loss of the antioxidant activity, of the of a thiol-containing electron to the TSA/AhpC protein (9.Cha M.K. Kim H.K. Kim I.H. J. Biol. Chem. 1995; 270: 28635-28641Abstract Full Text Full Text PDF PubMed Scopus (126) Google Scholar). such a antioxidant activity by TSA/AhpC BCP GS from the inactivation by a thiol MCO not by a MCO system The antioxidant activity of BCP in MCO system was by the of a Trx system of NADPH, Trx, and Trx reductase Taken together, these suggested that BCP is a new member of TSA/AhpC family and that the immediate electron to BCP is To the peroxidase activity of BCP, we measured the peroxidase activity of BCP toward hydroperoxide, and linoleic acid hydroperoxide in of the of peroxides in the presence of Trx The of all these peroxides as the concentration of BCP was is that the peroxides as the linoleic acid hydroperoxide was most at an equivalent concentration of To the of BCP various the peroxidase were in the presence of the Trx The NADPH rate as a function of BCP concentration not that the peroxidase activity of BCP be by the Trx The rate of peroxide by BCP was measured at the various concentrations of hydroperoxide, and linoleic acid hydroperoxide in the presence of the Trx The of showed that of BCP for hydroperoxide, and linoleic acid hydroperoxide were and for hydroperoxide, and linoleic acid hydroperoxide were and of The value max/K of BCP for H2O2, t-butyl hydroperoxide, and linoleic acid hydroperoxide were calculated to be and The higher value max/K of BCP hydroperoxide than of for H2O2 and t-butyl hydroperoxide that BCP has a general activity. we suggest that BCP acts as a thioredoxin-dependent the toward fatty acid hydroperoxide. most of TSA/AhpC exist in an TSA/AhpC such as Rhee S.G. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar) and E. coli (9.Cha M.K. Kim H.K. Kim I.H. J. Biol. Chem. 1995; 270: 28635-28641Abstract Full Text Full Text PDF PubMed Scopus (126) Google Scholar, H.K. Kim S.J. Lee J.W. Lee J.W. M.K. Kim I.H. Biochem. Biophys. Res. Commun. PubMed Scopus Google Scholar) exist in a BCP cysteine Cys-50, and as in 1. To the the cysteine of BCP, cysteine was with serine. The resulting and and were purified from the corresponding not To determine the cysteine the putative we the antioxidant activity of protein to protect the inactivation of GS by thiol MCO Only protein mutant resulted in the complete loss of the antioxidant activity In the presence of the Trx the peroxidase of mutant were determined by measuring the remaining amount of H2O2 or by the decrease of absorbance at 340 nm to the oxidation of NADPH protein not the peroxidase activity. The activity of mutant C50S, and that the Cys-45 is a primary site for the antioxidant of the TSA/AhpC family be into two such as and to the of the conserved the protein (3.Chae H.Z. Rhee S.G. Biofactors. 1994; 4: 177-180PubMed Google Scholar). The protein exists as a member of the TSA/AhpC family, as a protein one conserved and exists in Rhee S.G. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). To into the of a functional cysteine we reacted BCP with a modification or in the absence or presence of DTT The modification of BCP, of the presence or absence of DTT, resulted in the loss of the antioxidant activity, which suggested that the of the functional Cys-45 not the during the reaction as protein H.Z. Chung S.J. Rhee S.G. J. Biol. Chem. 1994; 269: 27670-27678Abstract Full Text PDF PubMed Google Scholar). was previously reported that the functional of as in exists in the of sulfenic acid as a which be reduced to by DTT Rhee S.G. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, Rhee S.G. Biol. PubMed Scopus Google Scholar). The functional of NADH peroxidase exists as A. J. Biol. Chem. Full Text PDF PubMed Google Scholar). To the that the functional Cys-45 of BCP exist in the of sulfenic acid of and NADH peroxidase, we reacted BCP with an NBD-Cl, as a for The reagent with and and the corresponding thiol which have absorbance nm for and nm for Poole L.B. PubMed Scopus Google Scholar). The of BCP protein DTT showed an absorbance at nm not suggesting the of in The BCP DTT resulted in the complete loss of the antioxidant activity Taken together, these could be as the of the functional Cys-45 as In to the BCP, we the containing the by of from the BCP at the absorbance The of the suggested that at least two BCP were reacted with NBD-Cl and resulted in the of the The a and were as the containing and using the mutant not The of the at nm at showed that the at 37 min the at min not the which that the a the not which the at a of the Poole L.B. PubMed Scopus Google Scholar). these suggested that the functional Cys-45 of BCP the exists in the of sulfenic acid its oxidation thiol peroxidase including E. coli p20, are by oxidative stress I.H. Kim K. Rhee S.G. Proc. Natl. Acad. Sci. U. S. A. 1989; PubMed Scopus Google Scholar, H.K. Kim S.J. Lee J.W. Lee J.W. M.K. Kim I.H. Biochem. Biophys. Res. Commun. PubMed Scopus Google Scholar, J. C. J. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, E. C. G. G. PubMed Scopus Google Scholar). To the by oxygen we the to and measured the in the cells cultured and in the activity was 3-fold in to the oxygen the expression level of the gradually elevated during exponential growth until mid-log phase growth, beyond which the expression level was The higher expression level of in the cells could be in of oxygen during the growth in which be Taken together, these suggested that BCP acting as an in vivo antioxidant is an protein in to oxygen To the in vivo antioxidant function of BCP, we bcp null mutant by an null mutant with the as a The of was by the the PCR products obtained from and cells and were than obtained from cells and not implying that the bcp were disrupted by the of The and strain were cultured LB The growth of null were than that of the cells The of null mutant cells were than that of cells The of null toward the various oxidants were The null showed hypersensitivity toward H2O2 hydroperoxide The and the peroxide hypersensitivity of the mutant could be complemented by the expression of bcp suggest that BCP acts as an antioxidant in of E. coli BCP and AhpC null toward various oxidants and and the by expression of and strain coli and for to LB H2O2 with H2O2 with t-butyl hydroperoxide (t-BOOH) the plasmid BCP of its the plasmid AhpC of its A and an overnight culture was to 0.1 A 600 then to 1 then 10 μl of culture was LB 10 μl of the culture by 1 was LB containing H2O2 and or and of the The new type of thiol peroxidase, to TSA/AhpC is the that against oxidative stress of hydroperoxide with the use of a thiol equivalent such as data are the first that BCP is a new bacterial member of the TSA/AhpC family, which the of hydroperoxide. with H2O2, t-butyl hydroperoxide, and linoleic acid hydroperoxide as activity to that with peroxidase of In mammals, peroxidase acts as a general hydroperoxide peroxidase to remove H2O2 and alkyl including fatty acid hydroperoxides (1.Halliwell B. Gutterridge J.M.C. Free Radical in Biology and Medicine. 2nd Ed. Clarendon Press, Oxford1989Google Scholar, 2.Michiels C. Raes M. Taussaint O. Remacle J. Free Radic. Biol. Med. 1994; 17: 235-248Crossref PubMed Scopus (1044) Google Scholar). The peroxidase activity of BCP toward linoleic acid hydroperoxide is with that of peroxidase toward linoleic acid hydroperoxide E. C. G. G. PubMed Scopus Google Scholar, J.W. Biophys. PubMed Scopus Google Scholar). the of we the reaction mechanism of BCP, which the of peroxides via cysteine sulfenic acid The sulfenic acid is reduced to by the of The reaction mechanism is to of and peroxidase, which the of peroxides via and Rhee S.G. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, O. K. A. A. J. Biol. PubMed Scopus Google Scholar). The sulfenic acid of peroxidase is reduced to by However, an immediate electron to are reaction mechanism of have suggested that the functional Cys-45 of BCP, which is in the reaction as a primary catalysis with the use of Trx as its immediate electron could exist in the of sulfenic acid and mutant activity, the of the of an between Cys-45 and other BCP as a of the BCP, TSA/AhpC exists in the of a in oxidation which the of an in the as TSA/AhpC H.Z. Chung S.J. Rhee S.G. J. Biol. Chem. 1994; 269: 27670-27678Abstract Full Text PDF PubMed Google Scholar). The sequence the conserved the bacterial BCP the that the other such as and Cys-99 be in the catalysis. The mechanism is as Trx is thiol peroxidase. In bacterial BCP as a TSA/AhpC is a novel type of thioredoxin-dependent peroxidase a general peroxide peroxidase activity. has been that E. coli two of the TSA/AhpC family and TSA/AhpC p20, exists in the periplasmic and the other member exists in the of E. coli (9.Cha M.K. Kim H.K. Kim I.H. J. Biol. Chem. 1995; 270: 28635-28641Abstract Full Text Full Text PDF PubMed Scopus (126) Google Scholar, M.K. Kim H.K. Kim I.H. J. PubMed Google Scholar). types and the of peroxides by Trx and (8.Jacobson F.S. Morgan R.W. Christman M.F. Ames B.N. J. Biol. Chem. 1989; 264: 1488-1496Abstract Full Text PDF PubMed Google Scholar, M.K. Kim H.K. Kim I.H. J. Biol. Chem. 1995; 270: 28635-28641Abstract Full Text Full Text PDF PubMed Scopus (126) Google Scholar). BCP and the Trx system as an immediate electron to the In to the peroxidase activity to remove H2O2 and t-butyl hydroperoxide, BCP showed fatty acid peroxidase activity. TSA/AhpC in