Lyases

Luận văn Thạc sĩ Sinh học "Nghiên cứu phân lập và sàng lọc các chủng vi khuẩn từ rong biển có khả năng sinh enzyme chuyển hóa Alginate từ rong nâu Việt Nam" trình bày các nội dung chính sau: Tìm và định danh được chủng vi khuẩn có nguồn gốc từ rong biển, có khả năng sinh alginate lyase; Xác định khả năng bẻ ngắn mạch alginate của enzyme thu nhận được trên cơ chất alginate chiết xuất từ rong nâu Việt Nam.

104p viabigailjohnson 10-06-2022 54 5   Download

Mời các bạn cùng tham khảo luận văn thạc sĩ Sinh học với đề tài "Nghiên cứu tách chiết Enzyme Alginate lyase từ vi sinh vật có trong rong biển và bước đầu ứng dụng nó để thủy phân alginate" để nắm nội dung kiến thức cần thiết.

79p hoydinha_hoihoidi 22-12-2014 238 38   Download

The plant enzyme phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) shows homology to histidine ammonia-lyase (HAL) whose structure has been solved by X-ray crystallography. Based on amino-acid sequence alignment of the two enzymes, mutagenesis was performed on amino-acid residues that were identical or similar to the active site residues in HAL to gain insight into the importance of this residues in PAL for substrate binding or catalysis. We mutated the following amino-acid residues: S203, R354, Y110, Y351, N260, Q348, F400, Q488 and L138....

11p system191 01-06-2013 65 4   Download

Two novel chondroitinases, chondroitin ABC lyase (EC 4.2.2.4) and chondroitin AC lyase (EC 4.2.2.5), have been purified from Bacteroides stercoris HJ-15, which was isolated from human intestinal bacteria with glycosaminoglycan degrading enzymes. Chondroitin ABC lyase was purified to apparent homogeneity by a combination of QAE-cellulose, CM-Sephadex C-50, hydroxyapatite and Sephacryl S-300 column chromatography with a final specific activity of 45.7 lmolÆmin)1Æmg)1.

7p system191 01-06-2013 52 5   Download

In the biosynthesis of the antiarrhythmic alkaloid ajmaline, polyneuridine aldehyde esterase (PNAE) catalyses a central reaction by transforming polyneuridine aldehyde into epivellosimine, which is the immediate precursor for the synthesis of the ajmalane skeleton. The PNAE cDNA was previously heterologously expressed in E. coli. Sequence alignments indicated that PNAE has a 43% identity to a hydroxynitrile lyase from Hevea brasiliensis, which is a member of the a/b hydrolase superfamily. The catalytic triad, which is typical for this family, is conserved.

8p system191 01-06-2013 36 4   Download

Institute for Organic Chemistry, University of Karlsruhe, Germany; 2Institute for Organic Chemistry, Budapest University of Technology and Economics, Hungary Elucidation of the 3D structure of histidine ammonia-lyase (HAL, EC 4.3.1.3) from Pseudomonas putida by X-ray crystallography revealed that the electrophilic prosthetic group at the active site is 3,5-dihydro-5-methylidene-4H-i´ midazol-4-one (MIO) [Schwede, T.F., Retey, J., Schulz, G.E. (1999) Biochemistry, 38, 5355 –5361].

9p system191 01-06-2013 50 3   Download

The prokaryotic ATP-citrate lyase is considered to be a key enzyme of the carbon dioxide-fixing reductive tricarboxylic acid (RTCA) cycle. Kinetic examination of the ATP-citrate lyase from the green sulfur bacterium Chlorobium limicola (Cl-ACL), an a4b4 heteromeric enzyme, revealed that the enzyme displayed typical Michaelis-Menten kinetics toward ATP with an apparent Km value of 0.21 ± 0.04 mM. However, strong negative cooperativity was observed with respect to citrate binding, with a Hill coefficient (nH) of 0.45. ...

8p research12 01-06-2013 43 4   Download

Cofactor requirements and enzyme kinetics have been studied of the novel, dual-action enzyme, the isomerizing phycoviolobilinphycoerythrocyanin-a84-cystein-lyase(PVB-PEC-lyase) fromMastigocladus laminosus, which catalyses both the covalent attachment of phycocyanobilin to PecA, the apo-a-subunit of phycoerythrocyanin, and its isomeri-zation to phycoviolobilin.

9p research12 23-04-2013 24 1   Download

The pathway of the oxidation of propionate to pyruvate in Escherichia coliinvolves five enzymes, only two of which, methylcitrate synthase and 2-methylisocitrate lyase, have been thoroughly characterized. Here we report that the isomerization of (2S,3S)-methylcitrate to (2R,3S)-2-methyl-isocitrate requires anovel enzyme,methylcitratedehydratase (PrpD), and the well-known enzyme, aconitase (AcnB), of the tricarboxylic acid cycle.

11p tumor12 22-04-2013 50 4   Download

A novel lyase, combining hydratase and aldolase activity, that converts citral intomethylheptenone and acetaldehyde, was purified from spores ofPenicillium digitatum.Remark-ably, citral lyase activitywas induced 118-fold by incubating nongerminating spores with the substrate, citral. This cofactor independent hydratase/aldolase, was purified and found tobe amonomeric enzymeof 31 kDa.Citral lyasehas aKmof 0.058mMand aVmaxof 52.6 UÆmg )1 .

8p tumor12 22-04-2013 37 2   Download

Human cytochrome P450 17a-hydroxylase (CYP17) cata-lyses not only the 17a-hydroxlation of pregnenolone and progesterone and the C17,20-side chain cleavage (lyase) of 17a-hydroxypregnenolone, necessary for the biosynthesis of C21-glucocorticoids and C19-androgens, but also catalyses the 16a-hydroxylation of progesterone. In efforts to under-stand the complex enzymology of CYP17, structure/func-tion relationships have been reported previously after expressingrecombinant DNAs, encodingCYP17 from various species, in nonsteroidogenic mammalian or yeast cells. ...

9p tumor12 22-04-2013 45 2   Download

Metabolite channelling, the process in which consecutive enzymes have confined substrate transfer in metabolic pathways, has been proposed as a biochemical mechanism that has evolved because it enhances catalytic rates and protects unstable intermediates. Results from experiments on the synthesis of radioactive urea [Cheung, C., Cohen, N.S. & Raijman, L (1989)J. Biol. Chem.264, 4038–4044] have been interpreted as implying channelling of arginine between argininosuccinate lyase and arginase in permeabi-lized hepatocytes. ...

9p tumor12 20-04-2013 35 1   Download

Salt-active acharan sulfate lyase (no EC number) has been purified fromBacteroides stercorisHJ-15,which was iso-lated from human intestinal bacteria with GAG degrading enzymes. The enzymewas purified toapparent homogeneity by a combination of QAE-cellulose,diethylaminoethyl (DEAE)-cellulose,CM-Sephadex C-50, HA ultrogel and phosphocellulose column chromatography with the final specific activity of 81.33lmolÆmin )1 Æmg )1 .

6p tumor12 20-04-2013 37 3   Download

[x-(Adenosyl)alkyl]cobalamins (homoadenosylcobalamins) are useful ana-logues of adenosylcobalamin to get information about the distance between Co and C5¢, which is critical for Co-C bond activation. In order to use them as probes for exploring the active sites of enzymes, the coenzymic properties of homoadenosylcobalamins for diol dehydratase and ethanol-amine ammonia-lyase were investigated. The kcat and kcat ⁄Kmvalues for adenosylmethylcobalamin were about 0.27% and 0.15% that for the regu-lar coenzyme with diol dehydratase, respectively. ...

10p fptmusic 12-04-2013 48 1   Download

Planarians are one of the simplest animal groups with a central nervous system. Their primitive central nervous system produces large quantities of a variety of neuropeptides, of which many are amidated at their C terminus. In vertebrates, peptide amidation is catalyzed by two enzymes [peptidylglycine a-hydroxylating monooxygenase (PHM) and peptidyl-a-hydroxylglycinea-amidating lyase] acting sequentially. In mammals, both enzymatic activities are contained within a single protein that is encoded by a single gene....

14p awards 05-04-2013 42 4   Download

The fermentation ofb-alanine by Clostridium propionicumproceeds via activation to the CoA-thiol ester, followed by deamination to acryloyl-CoA, which is also an intermediate in the fermentation ofl-alanine. By shifting the organism from the carbon and energy source a-alanine to b-alanine, the enzyme b-alanyl-CoA:ammonia lyase is induced 300-fold (30% of the soluble protein). The low basal lyase activity is encoded by theacl1gene, whereas the almost identicalacl2gene (six amino acid substi-tutions) is responsible for the high activity after growth on b-alanine....

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To shed light on the mechanism of isotopic exchange of a-protons in amino acids catalyzed by pyridoxal phosphate (PLP)-dependent enzymes, we studied the kinetics of quinonoid intermediate formation for the reactions of tyrosine phenol-lyase with L-phenylalanine, L-methionine, and theira-deuterated analogues inD2O, andwe compared the results with the rates of the isotopic exchange under the same conditions.Wehave found that, in theL-phenylalanine reaction, the internal returnof thea-proton is operative, and allowing for its effect, the exchange rate is accounted for satisfactorily....

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Jasmonic acid and its methyl ester are ubiquitous plant sig-nalling compounds necessary for the regulation of growth and development, as well as for the response of plants to environmental stress factors. To date, it is not clear whether methyl jasmonate itself acts as a signal or if its conversion to jasmonic acid is mandatory prior to the induction of a def-ense response. We have cloned a cDNA, encoding a methyl jasmonate-cleaving enzyme, from tomato cell suspension cultures.

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Little is known about the functions of DNA polymerasek (Pol k) recently identified in mammals. From the genomic sequence information of rice andArabidopsis, we found that Polkmay be the only member of the X-family in higher plants. We have succeeded in isolating the cDNA and recombinant protein of Polkin a higher plant, rice (Oryza sativaL. cv. Nipponbare) (OsPolk). OsPolkhad activities of DNA polymerase, terminal deoxyribonucleotidyl trans-ferase and deoxyribose phosphate lyase, a marker enzyme for base excision repair. ...

9p dell39 03-04-2013 54 3   Download

Chondroitin and dermatan sulfate (CS and DS) chains were isolated from bovine tracheal cartilage and pig intestinal mucosal preparations and frag-mented by enzymatic methods. The oligosaccharides studied include a disaccharide and hexasaccharides from chondroitin ABC lyase digestion as well as trisaccharides already present in some commercial preparations.

11p dell39 27-03-2013 37 4   Download