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| Dahiya,Neetu; Tewari,Rupinder; Tiwari,Ram P; Singh Hoondal,Gurinder. |
| Enterobacter sp. NRG4 was shown to excrete chitinase into the culture supernatant when cultivated in medium containing chitin. A 60 kDa extracellular chitinase was purified to homogeneity and characterized. The enzyme hydrolyzed swollen chitin, colloidal chitin, regenerated chitin and glycol chitin but did not hydrolyze chitosan. The chitinase exhibited Km and Vmax values of 1.43 mg ml-1 and 83.33 µM µg-1 h-1 for swollen chitin, 1.41 mg ml-1 and 74.07 µM µg-1 h-1 for colloidal chitin, 1.8 mg ml-1 and 40 µM µg-1 h-1 for regenerated chitin and 2.0 mg ml-1 and 33.33 µM µg-1 h-1 for glycol chitin, respectively. The optimal temperature and pH for activity were 45ºC and pH 5.5, respectively. Mg2+, K+ and Ca2+ stimulated chitinase activity by 13, 16 and 18%,... |
| Tipo: Journal article |
Palavras-chave: Chemical modification; Chitinase; Enterobacter sp. NRG4; Purification; Substrate binding. |
| Ano: 2005 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582005000200003 |
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| KOSOY,ANA; MÖLLER,CAROLINA; PERDOMO,DEISY. |
| Transducin (T), a GTP-binding protein involved in phototransduction of rod photoreceptor cells, is a heterotrimer arranged as two units, the a-subunit (Ta) and the bg-complex (Tbg). The role of the carboxyl groups in T was evaluated by labeling with N, N'-dicyclohexylcarbodiimide (DCCD) and 1-ethyl 3-(3-dimethylaminopropyl) carbodiimide (EDC). Only a minor effect on the binding of b, g-imido guanosine 5'-triphosphate (GMPpNp) to T was observed in the presence of the hydrophobic carbodiimide, DCCD. Similarly, the GMPpNp binding activity of the reconstituted holoenzyme was not significantly affected when Ta was combined with DCCD-treated Tbg. However, the binding of guanine nucleotides to the reconstituted T was ~50% inhibited when DCCD-labeled Ta was... |
| Tipo: Journal article |
Palavras-chave: Chemical modification; G-protein-coupled signaling; Group-specific labeling; Transducin; Visual process. |
| Ano: 2003 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602003000300010 |
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| Jezek,P.; Costa,A.D.T.; Vercesi,A.E.. |
| Chemical modifications were used to identify some of the functionally important amino acid residues of the potato plant uncoupling protein (StUCP). The proton-dependent swelling of potato mitochondria in K+-acetate in the presence of linoleic acid and valinomycin was inhibited by mersalyl (Ki = 5 µM) and other hydrophilic SH reagents such as Thiolyte MB, iodoacetate and 5,5'-dithio-bis-(2-nitrobenzoate), but not by hydrophobic N-ethylmaleimide. This pattern of inhibition by SH reagents was similar to that of brown adipose tissue uncoupling protein (UCP1). As with UCP1, the arginine reagent 2,3-butadione, but not N-ethylmaleimide or other hydrophobic SH reagents, prevented the inhibition of StUCP-mediated transport by ATP in isolated potato mitochondria or... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Plant mitochondria; Uncoupling protein; Chemical modification; Mitochondrial swelling; Reconstitution. |
| Ano: 2000 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2000001200003 |
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| Senni, Karim; Pereira, Jessica; Gueniche, Farida; Delbarre-ladrat, Christine; Sinquin, Corinne; Ratiskol, Jacqueline; Godeau, Gaston; Fischer, Anne-marie; Helley, Dominique; Colliec-jouault, Sylvia. |
| The therapeutic potential of natural bioactive compounds such as polysaccharides, especially glycosaminoglycans, is now well documented, and this activity combined with natural biodiversity will allow the development of a new generation of therapeutics. Advances in our understanding of the biosynthesis, structure and function of complex glycans from mammalian origin have shown the crucial role of this class of molecules to modulate disease processes and the importance of a deeper knowledge of structure-activity relationships. Marine environment offers a tremendous biodiversity and original polysaccharides have been discovered presenting a great chemical diversity that is largely species specific. The study of the biological properties of the... |
| Tipo: Text |
Palavras-chave: Marine bacteria; Marine algae; Exopolysaccharides; Sulfated polysaccharides; Structure; Chemical modification; Biological activity; Blue biotechnology; Cell therapy; Tissue engineering. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00048/15894/13316.pdf |
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| VICTOR,MAURICIO M.; DAVID,JORGE M.; SAKUKUMA,MARIA C.K.; COSTA-LOTUFO,LETÍCIA V.; MOURA,ANDREA F.; ARAÚJO,ANA J.. |
| ABSTRACT Natural steroids and triterpenes such as b-sitosterol, stigmasterol, lupeol, ursolic and betulinic acids were transformed into its hexanoic and oleic esters, to evaluate the influence of chemical modification towards the cytotoxic activities against tumor cells. The derivatives were evaluated against five tumor cell lines [OVCAR-8 (ovarian carcinoma); SF-295 (glioblastoma); HCT-116 (colon adenocarcinoma); HL-60 (leukemia); and PC-3 (prostate carcinoma)] and the results showed only betulinic acid hexyl ester exhibits cytotoxic potential activity. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Antitumor activity; Chemical modification; Derivative synthesis; Natural products esters. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652017000401369 |
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