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Photocontrol of alpha-chymotrypsin activity by covalently linked 2-carboxyazobenzene units

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Title Photocontrol of alpha-chymotrypsin activity by covalently linked 2-carboxyazobenzene units
 
Creator SINGH, AK
MADHUSUDNAN, KS
 
Subject photoregulation
bacteriorhodopsin
rhodopsin
light
 
Description alpha-Chymotrypsin exhibits photoswitchable catalytic activities in aqueous solution after eight of its thirteen backbone amino groups are covalently attached via amide linkage to trans-2-carboxyazobenzene [Ph-N=N-Ph-(o-CO2H), 1]. Irradiation of trans-azo-analogue of the enzyme in phosphate buffer (pH=7.6) at 314 nm gives the cis-azo-analogue of the enzyme with a quantum efficiency of 0.14 at ambient temperature. The trans-->cis photoreaction is reversed by irradiating the cis-au, enzyme at 430 nm. Both trans- and cis-forms of the ate-enzyme catalyze the hydrolysis of p-nitrophenyl acetate and the rates of this right-induced hydrolysis are found to be 7.77 and 6.98 (x 10(4)) mol/min respectively. Under similar conditions the hydrolysis rate of unmodified enzyme is found to be 8.97 x 10(4) moles/min. The photoisomerizable azobenzene units of 1 effect perturbation in the structure of alpha-chymotrypsin, thereby offering a convenient method to control its substrate binding affinity and hence its catalytic activity.
 
Publisher NATL INST SCIENCE COMMUNICATION
 
Date 2011-08-19T05:58:43Z
2011-12-26T12:56:05Z
2011-12-27T05:44:14Z
2011-08-19T05:58:43Z
2011-12-26T12:56:05Z
2011-12-27T05:44:14Z
1999
 
Type Article
 
Identifier INDIAN JOURNAL OF CHEMISTRY SECTION B-ORGANIC CHEMISTRY INCLUDING MEDICINAL CHEMISTRY, 38(8), 885-888
0376-4699
http://dspace.library.iitb.ac.in/xmlui/handle/10054/10248
http://hdl.handle.net/10054/10248
 
Language en