1.Enzymatic reduction of complex redox dyes using NADH-dependent reductase from Bacillus subtilis coupled with cofactor regeneration.
Bozic M1, Pricelius S, Guebitz GM, Kokol V. Appl Microbiol Biotechnol. 2010 Jan;85(3):563-71. doi: 10.1007/s00253-009-2164-8. Epub 2009 Aug 7.
Conventional vat dyeing involves chemical reduction of dyes into their water-soluble leuco form generating considerable amounts of toxic chemicals in effluents. In the present study, a new beta-nicotinamide adenine dinucleotide disodium salt (NADH)-dependent reductase isolated from Bacillus subtilis was used to reduce the redox dyes CI Acid Blue 74, CI Natural Orange 6, and CI Vat Blue 1 into their water-soluble leuco form. Enzymatic reduction was optimized in relation to pH and temperature conditions. The reductase was able to reduce Acid Blue 74 and Natural Orange 6 in the presence of the stoichiometrically consumed cofactor NADH; meanwhile, Vat Blue 1 required the presence of mediator 1,8-dihydroxyanthraquinone. Oxygen from air was used to reoxidize the dyes into their initial forms. The enzymatic reduction of the dyes was studied and the kinetic constants determined, and these were compared to the chemically-reduced leuco form. The enzyme responsible for the reduction showed homology to a NADH-dependent reductase from B.
2.Effects of activating cations and inhibitor on the allosteric regulation of rabbit muscle pyruvate kinase.
Li F1, Yu T, Jiang H, Yu S. Int J Biol Macromol. 2013 Sep;60:219-25. doi: 10.1016/j.ijbiomac.2013.05.028. Epub 2013 Jun 5.
Rabbit muscle pyruvate kinase (RMPK) requires activating cations for activity, but its activity can be allosterically inhibited. In this study, isothermal titration calorimetry (ITC) was used to examine the different effects of activating cations (K(+) or Mg(2+)) and inhibitor (Phe) on the allosteric regulation of RMPK. The ITC data reveal that the enthalpy change was greater for PEP binding to the active state compared to the inactive state. Meanwhile, the percentage of the active state increased with increasing concentration of K(+) or Mg(2+), whereas increasing Phe concentration had the opposite effect. In addition, we hypothesize that the activation of RMPK involves two processes. First, the interaction of Mg(2+) leads to a more exposed active site of RMPK. The process is rapid and only a small quantity of Mg(2+) can make RMPK transform to the intermediate state. Second, the subsequent binding of K(+) causes a critical orientation of the active site, which plays a more decisive role for PEP binding to RMPK than Mg(2+).
3.Huang-Lian-Jie-Du-Decotion induced protective autophagy against the injury of cerebral ischemia/reperfusion via MAPK-mTOR signaling pathway.
Wang PR1, Wang JS, Zhang C, Song XF, Tian N, Kong LY. J Ethnopharmacol. 2013 Aug 26;149(1):270-80. doi: 10.1016/j.jep.2013.06.035. Epub 2013 Jun 28.
ETHNOPHARMACOLOGICAL RELEVANCE: Huang-Lian-Jie-Du-Decotion (HLJDD, Hwangryun-Hae-Dok-Decotion in Japan), an ancient antipyretic and detoxifying traditional Chinese medicine formula, was reported to have protective effect on ischemic stroke.
4.DNA damage and estrogenic activity induced by the environmental pollutant 2-nitrotoluene and its metabolite.
Watanabe C1, Egami T, Midorikawa K, Hiraku Y, Oikawa S, Kawanishi S, Murata M. Environ Health Prev Med. 2010 Sep;15(5):319-26. doi: 10.1007/s12199-010-0146-1. Epub 2010 Apr 28.
OBJECTIVES: The environmental pollutant 2-nitrotoluene (2-NO(2)-T) is carcinogenic and reproductively toxic in animals. In this study, we elucidated the mechanisms of its carcinogenicity and reproductive toxicity.