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http://nopr.niscpr.res.in/handle/123456789/16591| Title: | Photocontrol of  -chymotrypsin activity by covalently linked 2-carboxyazobenzene units |
| Authors: | Singh, Anil K Madhusudnan, Kartha S |
| Issue Date: | Aug-1999 |
| Publisher: | NISCAIR-CSIR, India |
| Abstract: | -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-azo
enzyme at 430 nm. Both trans-and
cis-forms of the azo-enzyme catalyze
the hydrolysis of p-nitrophenyl
acetate and the rates of this light-induced hydrolysis are found to be 7.77 and
6.98 (×104) mol / min respectively.
Under similar conditions the
hydrolysis rate of unmodified enzyme is found to
be 8.97 × 104 moles/min. The photoisomerizable
awbenzene units of 1 effect perturbation
in the structure of -chymotrypsin, thereby offering a convenient method to
control its substrate binding affinity and hence its catalytic activity. |
| Page(s): | 885-888 |
| Appears in Collections: | IJC-B Vol.38B(08) [August 1999] |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| IJCB 38B(8) 885-888.pdf | 1.63 MB | Adobe PDF | View/Open |
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