Hello,
during an experiment I found myself in needing a standard curve of a kit for enzyme activity screening. The kit has a certain amount of substrate (cellulose) and I prepared different solutions of an enzyme (cellulase) to see the different effect of enzyme concentrations in terms of absorbance: once the test is finished, the surnatant is analyzed at 595 nm. From my data (enzyme concentrations and absorbances) I'd like to write an equation that can explain my model. What model could describe my situation better? I thought Michaelis-Menten equation would be a good fit, but in the equation I have substrate concentration and not enzyme concentration.
Best regards,
Maurizio
If you have been careful to measure the effect of enzyme concentration on the initial rate of the reaction, you should see that the initial rate is directly proportional to the enzyme concentration, as long as the enzyme concentration is far below the substrate concentration.
You want to use a linear fit to establish correspondence of enzyme activity with absorbance (analogous to Bradford assay for instance). Like seen here (just that you are using varying enzyme preparations to generate the standards for absorbance measurements)
https://www.jove.com/science-education/10188/calibration-curves
Cellulase is a general name for multiple enzymes and thus it is tricky to quantify, also the results may vary depending on your substrate (CMC or filter paper). I suggest you read through the following link and look at some papers:
Article Cellulase Assays
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