- Fingerprint lipolytic enzymes with chromogenic p-nitrophenyl esters of structurally diverse carboxylic acids
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A series of structurally diverse chromogenic esters, including a new compound (4-nitrophenyl 2-methylpentanoate), has been synthesized, constituting an array of 17 substrates which could be applied to rapidly fingerprint the activity of lipases or esterases to reveal their substrates specificity and functional characteristics. Combined with genetic technology such as "data mining" and directed evolution, such fingerprints might be a promising platform for discovery of potentially useful enzymes in industrial application. The fingerprint of commercially available Lipase-B from Candida antarctica as a model enzyme was first measured to confirm the reliability of this method. Then three new enzymes mined from genomic libraries were successfully fingerprinted, revealing the functional characteristics of those enzymes. Among them, the enzyme SrfAD was founded with specific substrate preference towards cycloalkyl carboxylic esters and aromatic esters, making it more promising in synthetic utilities than other tested enzymes.
- Qian, Le,Liu, Jia-Yan,Liu, Jia-Ying,Yu, Hui-Lei,Li, Chun-Xiu,Xu, Jian-He
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- HIGHER N-ACYL-L-AMINO ACID DERIVATIVES
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A preparative method is proposed for obtaining higher N-acylamino acids by reaction of free amino acids with fatty acid nitrophenyl esters.It was shown that these acids can transport positive ions through a liquid lipophilic medium.A direct method is proposed for obtaining fatty acid 4-nitrophenyl esters by boiling 4-nitrophenol and the fatty acid in xylene in a Soxhlet apparatus in the presence of an acid catalyst.
- Kochetkov, K. A.,Urmambetova, Zh. S.,Belikov, V. M.,Bakasova, Z. B.
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p. 2311 - 2316
(2007/10/02)
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- CATALYTIC EFFICIENCY OF SYNTHETIC MICELLAR CATALYSTS BEARING A MERCAPTO GROUP AS THE REACTION CENTER.
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In order to obtain a clue to understanding the micro-environmental effect on the reactivity of a mercapto group placed in a reaction center of enzymes, micellar surfactants bearing a mercapto group were synthesized and their catalytic activity in the degradation of p-nitrophenyl carboxylates was studied. N-Hexadecyl-N** alpha -glutaryl-L-cysteinamide (AM multiplied by (times) Cys-1) has an ability to form anionic micelles in aqueous media. The catalytic activity of AM multiplied by (times) Cys-1 was compared with that of another synthetic surfactant, N-hexadecanoyl-L-cysteine (AM multiplied by (times) Cys-2). These surfactants below their critical micelle concentations markedly accelerated the degradation of several p-nitrophenyl carboxylates. On the contrary, the concentration-rate profiles for the degradation of p-nitrophenyl dodecanoate (PNPL) as catalyzed by the surfactants indicate that the reactivity of the mercapto group is reduced upon formation of the anionic micelles.
- Murakami,Nakano,Matsumoto
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p. 2996 - 3004
(2007/10/05)
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