53-57-6Relevant articles and documents
Kinetic studies of the inhibition of a human liver 3α-hydroxysteroid/dihydrodiol dehydrogenase isozyme by bile acids and anti-inflammatory drugs
Miyabe,Amano,Deyashiki,Hara,Tsukada
, p. 9 - 12 (1995)
We have investigated the steady-state kinetics for a cytosolic 3α-hydroxysteroid/dihydrodiol dehydrogenase isozyme of human liver and its inhibition by several bile acids and anti-inflammatory drugs such as indomethacin, flufemanic acid and naproxen. Initial velocity and product inhibition studies performed in the NADP+-linked (S)-1-indanol oxidation at pH 7.4 were consistent with a sequential ordered mechanism in which NADP+ binds first and leaves last. The bile acids and drugs, competitive inhibitors with respect to the alcohol substrate, exhibited uncompetitive inhibition with respect to the coenzyme, with K(i) values less than 1 μM, whereas indomethacin exhibited noncompetitive inhibition (K(i) 24 μM). The kinetics of the inhibition by a mixture of the two inhibitors suggests that bile acids and drugs, except indomethacin, bind to overlapping sites at the active center of the enzyme-coenzyme binary complex.
Photochemical reduction of NADP+ by zinc protoporphyrin reconstituted myoglobin as a simple model of photosystem I
Nishiyama, Katsuhiko,Uchiyama, Miho,Mie, Yasuhiro,Taniguchi, Isao
, p. 357 - 358 (1999)
Photoinduced electron transfer between zinc protoporphyrin reconstituted myoglobin (Zn-Mb) and NADP+ functions as a model of photosystem I by forming NADPH. The reduction efficiency of NADP+ depended strongly on the solution pH, which was explained by the difference in the redox potential and/or the static interaction between Zn-Mb and a sacrificial donor triethanolamine (TEA).
Fabrication of novel electrochemical reduction systems using alcohol dehydrogenase as a bifunctional electrocatalyst
Yuan, Ruo,Kuwabata, Susumu,Yoneyama, Hiroshi
, p. 137 - 138 (1996)
Electrochemical reduction of NADP+ to NADPH and of NAD+ to NADH with current efficiencies of more than 97% has been achieved at alcohol dehydrogenase (ALDH) in the presence of acctophenone as an electron mediator. Addition of acetone or acctaldehyde as a substrate to the above electrolytic system allowed reduction of the substrate to the corresponding alcohol at ALDH accompanied by oxidation of the resulting NAD(P)H.
Design of artificial metalloenzymes for the reduction of nicotinamide cofactors
Basle, Mattias,Padley, Henry A.W.,Martins, Floriane L.,Winkler, Gerlof Sebastiaan,J?ger, Christof M.,Pordea, Anca
, (2021/04/19)
Artificial metalloenzymes result from the insertion of a catalytically active metal complex into a biological scaffold, generally a protein devoid of other catalytic functionalities. As such, their design requires efforts to engineer substrate binding, in addition to accommodating the artificial catalyst. Here we constructed and characterised artificial metalloenzymes using alcohol dehydrogenase as starting point, an enzyme which has both a cofactor and a substrate binding pocket. A docking approach was used to determine suitable positions for catalyst anchoring to single cysteine mutants, leading to an artificial metalloenzyme capable to reduce both natural cofactors and the hydrophobic 1-benzylnicotinamide mimic. Kinetic studies revealed that the new construct displayed a Michaelis-Menten behaviour with the native nicotinamide cofactors, which were suggested by docking to bind at a surface exposed site, different compared to their native binding position. On the other hand, the kinetic and docking data suggested that a typical enzyme behaviour was not observed with the hydrophobic 1-benzylnicotinamide mimic, with which binding events were plausible both inside and outside the protein. This work demonstrates an extended substrate scope of the artificial metalloenzymes and provides information about the binding sites of the nicotinamide substrates, which can be exploited to further engineer artificial metalloenzymes for cofactor regeneration. Synopsis about graphical abstract: The manuscript provides information on the design of artificial metalloenzymes based on the bioconjugation of rhodium complexes to alcohol dehydrogenase, to improve their ability to reduce hydrophobic substrates. The graphical abstract presents different binding modes and results observed with native cofactors as substrates, compared to the hydrophobic benzylnicotinamide.
Selective Usage of Isozymes for Stress Response
Zhang, Yugang,Lin, Zhewang,Wang, Miao,Lin, Hening
, p. 3059 - 3064 (2018/11/23)
Isozymes are enzymes with similar sequences that catalyze the same reaction in a given species. In Saccharomyces cerevisiae, most isozymes have major isoforms with high expression levels and minor isoforms with little expression under normal growth conditions. In a proteomic study aimed at identifying yeast protein regulated by rapamycin, we found an interesting phenomenon, that, for several metabolic enzymes, the major isozymes are downregulated while the minor isozymes are upregulated. Through enzymological and biochemical studies, we demonstrate that a rapamycin-upregulated enolase isozyme (ENO1) favors gluconeogenesis and a rapamycin-upregulated alcohol dehydrogenase isozyme (ALD4) promotes the reduction of NAD+ to NADH (instead of NADP+ to NADPH). Gene deletion study in yeast showed that the ENO1 and ALD4 are important for yeast survival under less-favorable growth conditions. Therefore, our study highlights the different metabolic needs of cells under different conditions and how nature chooses different isozymes to fit the metabolic needs.
A solar light-driven, eco-friendly protocol for highly enantioselective synthesis of chiral alcohols via photocatalytic/biocatalytic cascades
Choudhury, Sumit,Baeg, Jin-Ook,Park, No-Joong,Yadav, Rajesh K.
, p. 4389 - 4400 (2014/09/29)
The judicious utilization of solar light for the asymmetric synthesis of optically active compounds by imitating natural photosynthesis introduces a new concept that harnesses this renewable energy in vitro for ultimate transformation into chiral chemical bonds. Herein, we present a comprehensive description of such a biomimetic endeavor towards the design and construction of an asymmetric artificial photosynthesis system that comprises an efficient method of nicotinamide cofactor (NADPH) regeneration under visible light employing a graphene-based light harvesting photocatalyst and its subsequent utilization in an enzyme-catalyzed asymmetric reduction of prochiral ketones to expediently furnish the corresponding chiral secondary alcohols. A detailed optimization study revealed a major dependency of the reaction outcome on the amount of cofactor, photocatalyst and enzyme used, as well as the mode of their addition. A series of structurally diverse ketones bearing an array of (hetero)aryl/alkyl substituents proved to be highly suitable to our photocatalytic-biocatalytic cascade approach, providing (R/S)-1-(hetero)aryl/ alkylethanols in excellent enantioselectivities (ee ～ 95->99.9%) under mild and environmentally benign conditions. To the best of our knowledge, the synthesis of these enantiopure alcohols employing a visible-light-driven nicotinamide cofactor regeneration strategy has been reported for the first time. Such enantioenriched alcohols act as versatile chiral building blocks for the synthesis of compounds having industrial and pharmaceutical relevance. In addition, this solar-to-chiral chemicals prototype appears advantageous from ecological and economical perspectives. We describe mechanistic pathways to demonstrate how the present catalytic synthesis protocol functions through perfect orchestration between visible-light-driven photocatalysis and biocatalysis to be successively applied in inducing asymmetry in an achiral molecule for the ultimate goal of solar energy utilization in the synthesis of valuable chiral fine chemicals. This work highlights the potential advantages of a bioinspired system to the pertinence of solar energy in asymmetric transformations leading to enantioenriched alcohol precursors, and thus opens up a new field of research that might emerge as an important breakthrough with promising implications towards generating a sustainable and non-fossil/non- nuclear energy future. the Partner Organisations 2014.
