scholarly journals l(+)-Mandelate dehydrogenase from Rhodotorula graminis: purification, partial characterization and identification as a flavocytochrome b

1993 ◽  
Vol 293 (2) ◽  
pp. 455-460 ◽  
Author(s):  
M Yasin ◽  
C A Fewson

L(+)-Mandelate dehydrogenase was purified to homogeneity from the yeast Rhodotorula graminis KGX 39 by a combination of (NH4)2SO4 fractionation, ion-exchange and hydrophobic-interaction chromatography and gel filtration. The amino-acid composition and the N-terminal sequence of the enzyme were determined. Comprehensive details of the sequence determinations have been deposited as Supplementary Publication SUP 50172 (4 pages) at the British Library Document Supply Centre, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1993) 289, 9. The enzyme is a tetramer as judged by comparison of its subunit M(r) value of 59,100 and native M(r) of 239,900, estimated by SDS/PAGE and gel filtration respectively. There is one molecule of haem and approx. one molecule of non-covalently bound FMN per subunit. 2,6-Dichloroindophenol, cytochrome c and ferricyanide can all serve as electron acceptors. L(+)-Mandelate dehydrogenase is stereospecific for its substrate. D(-)-Mandelate and L(+)-hexahydromandelate are competitive inhibitors. The enzyme has maximum activity at pH 7.9 and it has a pI value of 4.4. HgCl2 and 4-chloromercuribenzoate are potent inhibitors, but there is no evidence that the enzyme is subject to feedback inhibition by potential metabolic effectors. The evidence suggests that L(+)-mandelate dehydrogenase from R. graminis is a flavocytochrome b which is very similar to, and probably (at least so far as the haem domain is concerned) homologous with, certain well-characterized yeast L(+)-lactate dehydrogenases, and that the chief difference between them is their mutually exclusive substrate specificities.

2017 ◽  
Vol 18 (2) ◽  
pp. 1-10 ◽  
Author(s):  
Dzun Noraini Jimat ◽  
Intan Baizura Firda Mohamed ◽  
Azlin Suhaida Azmi ◽  
Parveen Jamal

A newly bacterial producing L-asparaginase was successful isolated from Sungai Klah Hot Spring, Perak, Malaysia and identified as Bacillus sp. It was the best L-asparaginase producer as compared to other isolates. Production of L-asparaginase from the microbial strain was carried out under liquid fermentation. The crude enzyme was then centrifuged and precipitated with ammonium sulfate before further purified with chromatographic method. The ion exchange chromatography HiTrap DEAE-Sepharose Fast Flow column followed by separation on Superose 12 gel filtration were used to obtain pure enzyme. The purified enzyme showed 10.11 U/mg of specific activity, 50.07% yield with 2.21 fold purification. The purified enzyme was found to be dimer in form, with a molecular weight of 65 kDa as estimated by SDS-PAGE. The maximum activity of the purified L-asparaginase was observed at pH 9 and temperature of 60°C.


2005 ◽  
Vol 37 (6) ◽  
pp. 363-370 ◽  
Author(s):  
Ye-Yun Li ◽  
Chang-Jun Jiang ◽  
Xiao-Chun Wan ◽  
Zheng-Zhu Zhang ◽  
Da-Xiang Li

Abstractβ-Glucosidases are important in the formation of floral tea aroma and the development of resistance to pathogens and herbivores in tea plants. A novel β-glucosidase was purified 117-fold to homogeneity, with a yield of 1.26%, from tea leaves by chilled acetone and ammonium sulfate precipitation, ion exchange chromatography (CM-Sephadex C-50) and fast protein liquid chromatography (FPLC; Superdex 75, Resource S). The enzyme was a monomeric protein with specific activity of 2.57 U/mg. The molecular mass of the enzyme was estimated to be about 41 kDa and 34 kDa by SDS-PAGE and FPLC gel filtration on Superdex 200, respectively. The enzyme showed optimum activity at 50 °C and was stable at temperatures lower than 40 °C. It was active between pH 4.0 and pH 7.0, with an optimum activity at pH 5.5, and was fairly stable from pH 4.5 to pH 8.0. The enzyme showed maximum activity towards pNPG, low activity towards pNP-Galacto, and no activity towards pNP-Xylo.


1998 ◽  
Vol 331 (2) ◽  
pp. 513-519 ◽  
Author(s):  
Alberto VITALI ◽  
Bruno BOTTA ◽  
Giuliano DELLE MONACHE ◽  
Sabrina ZAPPITELLI ◽  
Paola RICCIARDI ◽  
...  

An acidic peroxidase (EC 1.11.1.7) produced by cell suspension cultures of Cassia didymobotrya(wild senna) was purified from culture medium collected on the 29th day. The enzyme was shown to be a glycoprotein with a pI of 3.5, a molecular mass of approx. 43 kDa by SDS/PAGE and 50 kDa by gel filtration. The N-terminal sequence was very similar to those of other plant peroxidases. The peroxidase was characterized by a high specificity towards coniferyl alcohol and other natural phenolics such as guaiacol and ferulic and caffeic acids. These findings suggest that the enzyme is involved in lignification processes of the cell wall. Moreover, the enzyme was able to catalyse the oxidation of 4,3´,4´-trihydroxychalcone and 4,3´,4´-trihydroxy-3-methoxychalcone to the corresponding 3,3´-biflavanones, as mixtures of racemic and mesoforms.


1996 ◽  
Vol 199 (2) ◽  
pp. 311-318 ◽  
Author(s):  
R L Miller ◽  
R Vogt

Freshwater extracts of starfish ovaries were used to purify the sperm-attracting peptide 'startrak' from Pycnopodia helianthoides using hydrophobic interaction chromatography and DEAE-high-pressure liquid chromatography. Partially purified attractant had a molecular mass of 13 kDa, estimated from gel filtration and polyacrylamide gel electrophoresis results. The purified attractant was subjected to amino acid analysis and direct sequencing, and was found to consist largely of a single peptide composed of an estimated 127 residues based on a molecular mass of 13kDa. An N-terminal sequence of amino acids from positions 3 to 34 was obtained and synthesized as: NH2-Ala-Glu-Leu-Gly-Leu-Cys-Ile-Ala-Arg-Val-Arg-Gln-Gln-Asn-Gln-Gly-Gln- Asp-Asp-Val-Ser-Ile-Tyr-Gln-Ala-Ile-Met-Ser-Gln-Cys-Gln-Ser-COOH. The synthetic peptide possessed sperm-attracting activity 130 times greater than the activity of partially purified startrak and showed a pattern of species-specificity of sperm chemotaxis similar to that of startrak. Antibody prepared against synthetic peptide removed the sperm-attracting activity from crude and partially purified preparations of startrak. The partial sequence of startrak was not homologous with that of any of the known echinoid sperm motility-activating peptides.


1997 ◽  
Vol 327 (1) ◽  
pp. 185-191 ◽  
Author(s):  
Hanne B.Aa. THEILGAARD ◽  
Klaus N. KRISTIANSEN ◽  
Claus M. HENRIKSEN ◽  
Jens NIELSEN

δ-(L-α-Aminoadipyl)-L-cysteinyl-d-valine synthetase (ACVS) from Penicillium chrysogenum was purified to homogeneity by a combination of (NH4)2SO4 precipitation, protamine sulphate treatment, ion-exchange chromatography, gel filtration and hydrophobic interaction chromatography. The molecular mass of ACVS was estimated with native gradient gel electrophoresis and SDS/PAGE. The native enzyme consisted of a single polymer chain with an estimated molecular mass of 470 kDa. The denatured enzyme had an estimated molecular mass of 440 kDa. The influence of different reaction parameters such as substrates, cofactors and pH on the activity of the purified ACVS was investigated. The Km values for the three precursor substrates L-α-aminoadipic acid, L-cysteine and L-valine were determined as 45, 80 and 80 μM respectively, and the optimal assay concentration of ATP was found to be 5 mM (with 20 mM MgCl2). The dimer of the reaction product bis-δ-(L-α-aminoadipyl)-l-cysteinyl-D-valine (bisACV) gave feedback inhibition of the purified ACVS; the inhibition parameter KbisACV was determined as 1.4 mM. Furthermore dithiothreitol was shown to inhibit the purified ACVS. From the addition of a glucose pulse to a steady-state glucose-limited continuous culture of P. chrysogenum it was found that there is glucose repression of the synthesis of ACVS and that there must be a constant turnover of ACVS owing to synthesis and degradation.


1990 ◽  
Vol 271 (3) ◽  
pp. 797-801 ◽  
Author(s):  
B C Beaubien ◽  
P D Collins ◽  
P J Jose ◽  
N F Totty ◽  
J Hsuan ◽  
...  

An inflammatory reaction was induced in vivo by injection of zymosan into the peritoneal cavity of the rabbit. The inflammatory exudate was found to contain oedema-inducing and neutrophil chemoattractant activity when assayed in rabbit skin in vivo, using 125I-albumin and 111In-neutrophils. This activity was additional to that of complement fragment C5a, which was removed by an affinity gel. Two chemoattractants were isolated by cation-exchange, gel-filtration and reversed-phase h.p.l.c. One of these, which ran as a single band of 6-8 kDa on SDS/PAGE, was subjected to N-terminal sequence analysis without reduction and alkylation of cysteine residues. Positive identification of 28 of the first 31 amino acids revealed a rabbit homologue of interleukin-8 (75% sequence identity with human interleukin-8). The demonstration of interleukin-8 as a major neutrophil chemoattractant in an inflammatory reaction in vivo provides the basis for further investigations into the role of this cytokine in the inflammatory process.


1996 ◽  
Vol 313 (1) ◽  
pp. 193-199 ◽  
Author(s):  
Mausumi BHARADWAJ ◽  
Dwaipayan BHARADWAJ ◽  
Ratha N. HATI

A membrane protease possessing thrombin-like activity was purified to homogeneity from mitochondria of rat submaxillary gland. The molecular mass of the enzyme was determined to be 45 kDa by SDS/PAGE under reducing conditions and by gel filtration on a Sephadex G-100 column. The enzyme is a glycoprotein and has an isoelectric point of 3.25. Maximum activity was observed at pH 10.5. Inhibition by di-isopropyl fluorophosphate, benzamidine, aprotinin and antipain suggested the enzyme to be a serine protease. Other inhibitors such as EDTA, soya-bean trypsin inhibitor, lima-bean trypsin inhibitor, TosLysCH2Cl and chymostatin did not alter the activity. The enzyme showed affinity towards different synthetic substrates (p-nitroanilide derivatives) containing arginine at the P1 position. Kinetic studies revealed that kcat./Km was highest with the substrate N-Bz-Phe-Val-Arg-p-nitroanilide. The enzyme exhibits significant plasma-coagulating activity. The coagulation initiated by the enzyme was not altered by concanavalin A, indicating that the carbohydrate moiety of the enzyme is not essential for this reaction. Further, this enzyme can catalyse the formation of fibrin clots from purified fibrinogen, which describes its thrombin-like activity. However, an antibody raised against the purified enzyme inhibited the plasma-clotting as well as fibrinogen-clotting activity of the enzyme. Fibrinogen coagulation by the enzyme was blocked in the presence of aprotinin, a protease inhibitor. Release of fibrinopeptides A and B from bovine fibrinogen by the enzyme has been shown by HPLC analysis. Our studies reveal that the enzyme reported here differs from trypsin, chymotrypsin and other mitochondrial proteases reported so far.


2003 ◽  
Vol 70 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Ashok K Mohanty ◽  
Utpal K Mukhopadhyay ◽  
Jai K Kaushik ◽  
Sunita Grover ◽  
Virender K Batish

Chymosin, an aspartyl proteinase, is used for curdling of milk and manufacture of cheese. We report the purification and the physicochemical properties of chymosin isolated from the abomasal tissue of buffalo calves. The enzyme preparation extracted from buffalo abomasal tissues could be purified 29–fold using anion exchange and gel filtration chromatography. The molecular weight of the purified enzyme was 35·6 kDa on SDS-PAGE. Partial N-terminal amino acid sequence of the first eight amino acid sequences of buffalo chymosin was identical to the first eight amino acid sequences of cattle chymosin. Buffalo chymosin exhibited a skewed bell-shaped stability profile as a function of temperature with maximum activity near 55 °C. Milk clotting activity decreased gradually as pH increased. The enzyme became completely inactive, however, above pH 7·0. The ratio of milk clotting to proteolytic activity was 3·03. When compared with cattle chymosin, there were subtle differences in the stability and relative proteolytic activity of buffalo chymosin.


1996 ◽  
Vol 42 (10) ◽  
pp. 1039-1044 ◽  
Author(s):  
Eliane Ferreira Noronha ◽  
Cirano José Ulhoa

β-1,3-Glucanases are produced by Trichoderma harzianum when it is grown in the presence of chitin or isolated cell wall from fungi. An endo-β-1,3-glucanase from the culture filtrate of T. harzianum was purified by gel filtration on Sephacryl S-200, followed by hydrophobic interaction chromatography on phenyl-Sepharose. A typical procedure provided 134-fold purification with a 3.6% yield. The molecular mass of the purified endo-β-1,3-glucanase was found to be approximately 36 kDa, as estimated by sodium dodecyl sulfate – polyacrylamide gel electrophoresis on a 10% w/v slab gel. The enzyme was active toward glucans containing β-1,3-linkages and hydrolysed laminarin to form oligosaccharides. The Km and Vmax values for β-1,3-ghicanases, using laminarin as substrate, was 1.18 mg∙mL−1 and 1.26 U∙mL−1, respectively. The pH optimum for the enzyme was pH 4.4 and maximum activity was obtained at 45–50 °C. Enzyme activity was strongly inhibited in the presence of HgCl2 and stimulated by cations such as Zn2+ and Ca2+.Key words: endo-β-1,3-glucanase, Trichoderma harzianum, purification, characterization.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Mohsen Helmy Selim ◽  
El-Zahraa Karm Eldin ◽  
Moataza Mahmoud Saad ◽  
El-Sayed Eliwa Mostafa ◽  
Yosrea Hassan Shetia ◽  
...  

The aim of the present study is to purify L-methioninase from Candida tropicalis 34.19-fold with 27.98% recovery after ion exchange chromatography followed by gel filtration. The purified enzyme revealed a single band on SDS-PAGE gel with a molecular weight of 46 KDa. Its optimum temperature was 45 to 55 and thermal stability was 55°C for 15 min. The enzyme had optimum pH at 6.5 and stability at a pH range of 5.5 to 7.0 for 24 hr. The maximum activity was observed with substrate concentration of 30 µM and Km was 0.5 mM. The enzyme was strongly inhibited by Cd+2 and Cu+2 while it was enhanced by Na+, Ni+2, and Mg+2 at 10 mM while Ca+2 had slight activation at 20 mM. In addition, the potential application of the L-methioninase as an anticancer agent against various types of tumor cell lines is discussed.


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