Microscopic rate‐constants for substrate binding and acylation in cold‐adaptation of trypsin I from Atlantic cod
Temperature imposes limits on where life can thrive and this is evident in the evolution of the basic structural properties of proteins. Cold‐adaptation of enzymes is one example, where the catalytic rate constant ( k cat ) is increased compared with hot‐acclimated homologous under identical assay c...
| Published in: | FEBS Letters |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
2006
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1016/j.febslet.2006.07.043 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1016%2Fj.febslet.2006.07.043 https://febs.onlinelibrary.wiley.com/doi/pdf/10.1016/j.febslet.2006.07.043 |
| Summary: | Temperature imposes limits on where life can thrive and this is evident in the evolution of the basic structural properties of proteins. Cold‐adaptation of enzymes is one example, where the catalytic rate constant ( k cat ) is increased compared with hot‐acclimated homologous under identical assay conditions. Trypsin I from Atlantic cod ( Gadus morhua ) has catalytic efficiency ( k cat / K m ) for amide hydrolysis that is 17‐fold larger than observed for bovine trypsin. Here, the individual rate‐constants for association of substrate ( k 1 ), dissociation of substrate ( k −1 ), and acylation of the enzyme ( k 2 ) have been determined using benzoyl‐Arg‐ p ‐nitroanilide or benzyloxycarbonyl‐Gly‐Pro‐Arg‐ p ‐nitroanilide as substrates. Rather unexpectedly, by far the largest difference (37‐fold increase) was observed in k 1 , the rate constant for binding of substrate. The cold‐adaptation of the dissociation and catalytic steps were not as prominent (increased by 3.7‐fold). The length of substrate did have an effect by increasing the reaction rate by 70‐fold, and again, the step most affected was the initial binding‐step. |
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