Purification and biochemical properties of phospholipase D (PLD57) produced by Streptomyces sp. CS-57.
ABSTRACT Streptomyces sp. CS-57, which was isolated from Korean soil, was found to produce phospholipase D (PLD57) as an extracellular enzyme when cultured in medium containing 2% glucose, 1.5% yeast extract, 0.5% trypton, and 0.1% calcium carbonate at 28 degrees C, and 160-rpm. PLD57 was purified using Sepharose CL-6B column chromatography, and DEAE-Sepharose CL-6B ion exchange column chromatography. The specific activity of the purified enzyme increased 6.7 fold with 3% recovery. The purified enzyme was then analyzed using 12% SDS-PAGE, which revealed that the molecular mass of the purified enzyme was 55 kDa. PLD57 showed both hydrolytic (H) and transphosphatidylation (T) activity, and the optimum temperatures of these activities were found to be 45 degrees C and 35 degrees C, respectively. Similarly, both of these activities were found to be optimal at a pH of 7.5. In addition, even after being heat treated at 45 degrees C for up to 2 h, the enzyme activity remained at 100%, and the H-activity was found to be stable at a pH of 6 to 8. Further, enzyme activity occurred in the presence of EDTA, indicating that metal ions are not required for their activity, although some metal ions did marginally increase the activity. Enzyme activity also increased by 75% in the presence of Triton-X 100 at a concentration of 0.375 %; however, none of the other detergents evaluated in this study were found to enhance enzyme activity.
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ABSTRACT: A novel metal ion-independent phospholipase B (PLB684 ) from Streptomyces sp. strain NA684 was purified 264-fold from the culture supernatant with 2.85% recovery (6,330 U/mg-protein). The enzyme functions as a monomer with a molecular weight of 38.9 kDa. Maximum activity was found at pH 8.4 and 50 °C. The substrate specificity was in the following order: phosphatidylcholine ≥ phosphatidic acid ≥ lysophosphatidylcholine > phosphatidylserine > phosphatidylinositol > phosphatidylglycerol. The enzyme did not hydrolyze phosphatidylethanolamine, tristearin and dipalmitin. PLB684 hydrolyzed lysophosphatidylcholine and diacylphosphatidylcholine, and lysophosphatidylcholine was primarily produced during the early stages of phosphatidylcholine hydrolysis. The apparent Km , Vmax and kcat for hydrolysis of dimyristoyl phosphatidic acid were 14.5 mM, 15.8 mmol min(-1) mg-protein(-1) and 1.02 × 10(4) s(-1) , respectively. The positional specificity of 1-palmitoyl-2-oleoyl-sn-glycero-3- phosphocholine hydrolysis was investigated using gas chromatography. In the reaction equilibrium, the molar ratio of released fatty acids (sn-1:sn-2) was 45:55. The open reading frame of the gene is 1,239 bp in length and codes for a 30-amino-acid signal peptide and a 382-amino-acid mature enzyme. The deduced amino acid sequence of PLB684 shows 60% identity to a putative uncharacterized SGNH esterase of Streptomyces auratus AGR0001 (UniProt accession no. J1RQY0). The extracellular production of PLB684 was achieved using a pUC702 expression vector and Streptomyces lividans as the host. Mutagenesis analysis showed that Ser12 is essential for the catalytic function of PLB684 and the active site may include residues Ser330 and His332. This article is protected by copyright. All rights reserved.FEBS Journal 06/2013; · 3.99 Impact Factor
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ABSTRACT: A gene encoding a putative phospholipase D was isolated from Bacillus licheniformis and cloned into pGEM-T easy vector. The gene was expressed in E. coli BL21 (DE3) using a pET-21(a) vector containing His6 tag. Affinity purification of the recombinant phospholipase D with nickel-nitrilotriacetic acid (Ni-NTA) resin resulted major one-band by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The purified enzyme showed a molecular weight of 44 kDa. The optimum activity of enzyme was around pH 7.0 and the enzyme was also the most stable around this condition. The optimum temperature was about and the enzyme still showed considerable activities at wide range of temperature. Among various detergents, Triton X-100 significantly increased the enzyme activity, resulting in 181% activity of control at 0.6 mM of the detergent. Calcium ion did not significantly affect the enzyme activity, suggesting that the enzyme might be classified into -independent PLD.Journal of Applied Biological Chemistry 06/2011; 54(2).
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ABSTRACT: A 60kDa phospholipase D (PLD) was obtained from Streptomyces olivochromogenes by one-step chromatography on Sepharose CL-6B. Maximal activity was at pH 8 and 75°C and the enzyme was stable from pH 7 to 13 and from 55 to 75°C. Thermal and pH stability with temperature optimum of the enzyme were highest among Streptomyces PLDs reported so far. The activity was Ca2+-dependent and enhanced by detergents. The Km and Vmax values for phosphatidylcholine were 0.6mM and 650μmolmin−1mg−1, respectively. In addition, the enzyme also revealed transphosphatidylation activity, which was optimum at pH 8 and 50°C. The first 15 amino acid residues of the N terminal sequence were ADYTPGAPGIGDPYY, which are significantly different from the other known PLDs. The enzyme may therefore be a novel PLD with potential application in the lipid industry.Biotechnology Letters 03/2009; 31(3):429-435. · 1.74 Impact Factor