Hello,

Can anyone please advise me on a couple of things I'm confused about regarding simple enzyme experiments?

In an experiment (with repeats) to investigate the effect of a certain factor on the rate of an enzyme reaction, must I work out the rate of the reaction by taking the reciprocal of the mean time of the repeats if no measurement has been made of the amount of substrate that has disappeared or amount of product that has formed? i.e Must I:

First convert each of the repeat time values into seconds (the unit for rate)

Calculate the mean value of the repeats

Calculate the rate of reaction by taking the reciprocal of the mean time

i.e. 1/mean time

Would this (taking the reciprocal of the time) be the right way to calculate the rate of the reaction in an experiment where the rate cannot be calculated the usual way?; that is by using the normal equation: change (e.g. amount of product produced)/time

Also, how can I use an enzyme solution (labeled 'enzyme solution 100%') and water to produce a number of different dilutions? If I am asked to make up 10cm^3 of each concentration, what would I be expected to do to make these dilutions?

Would it be a matter of mixing say 8cm^3 of enzyme solution and 2cm^3 of water for an 80% concentration, 6cm^3 enzyme solution and 4cm^3 for a 60% concentration, 4cm^3 enzyme solution and 6cm^3 water for a 40% concentration etc.

Or am I wrong? Is it perhaps more complicated than that?

Thank you