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Chymotrypsin and trypsin specificity - help!

Posted: Wed Dec 30, 2020 2:11 am
by hlaurenc
I recently carried out an investigation into the specificity of chymotrypsin and trypsin which I am in the process of writing up. In short, combined substrate with enzyme, incubated for 15 mins and measured at 430nm. Used trendline equation to determine mmol products formed per minute.

N-benzoyl-DL-arginine-p-nitroanilide (BAPNA) and N-succinyl-L-phenylalanine-p-nitroanilide (NSPLN) were the synthetic substrates used to be recognised by trypsin and chymotrypsin, respectively.

Results came back as expected; however, when doing the opposing combinations (chymotrypsin-BAPNA and trypsin-NSLPN), activity levels were recorded. I have been racking my brains and books for hours and hours and can't seem to understand how there would be any activity levels as trypsin doesn't cleave at phenylalanine, nor chymotrypsin at arginine.

I'm a first year 'mature' student undergraduate returning to university with no science background - this part is mind boggling!

Thank you in advance :)