Enzyme activity calculation
 FAQ Calendar Search Today's Posts Mark Forums Read

#1
February 24th, 2008, 04:29
 sootyandsweep Junior Member Join Date: Feb 2008 Posts: 3
Enzyme activity calculation

Hi,
I need help calculating step 3, the moles formed per min, per ml of initial solution from the moles formed per min of the diluted solution.

Enzyme activity calculation in 4 steps

step 1 - calculating the change in conc per min from the diluted solution
A = 0.105min-1

c = A/el 0.105/6620x1 = 1.586x10-5

step 2 number of moles formed per min from the diluted solution

n=c x v diluted solution = 1ml = 0.001 litres

1.586x10-5 x 0.001 = 1.866x10-8 mol min-1

step 3- Number of moles formed per min, per ml of initial solution ?????

Initial solution is 20ul = 0.02ml

N.B. Apparently the answer is 7.93x10-7 mol ml-1 min-1- but how to get there?

Step - 4 - conversion to correct units = enzyme activity

Thanks
:?:
#2
March 2nd, 2008, 08:33
 sootyandsweep Junior Member Join Date: Feb 2008 Posts: 3

Anyone??
#3
March 3rd, 2008, 15:34
 Hix3r Member Join Date: Apr 2007 Location: Hungary Posts: 40

Okay I can't really understand this yet but here it is:

If you don't understand the process or the question, always try to get a lead from the unit. At step 1 the unit of the answer is mol/(litre*minute). It is almost what we need at step 3 only we need it like this mol/(millilitre*minute), so what do we do, we take the answer and divide it by 1000. Okay, now so we must put our thing into the first equation and then divide it by 1000.

So what changed now, that we have an initial solution and not a diluted one? Of course the volume! So the equation changes accordingly, if I deduced right:

concentration change per minute in initial solution = 0.105/(6620*0.02) = 7.93*10^-4 mol/(litre*minute)

now we divide it by 1000:

concentration (in mol/ml) change per minute in initial solution:
7.93*10^-4/1000 = 7.93-10^-7 mol/(ml*minute)

And there you have it the answer. I don't know what ther correct units are but there are two units of enzyme activity. One is katal. Which is number of mole of products per second. The other unit of enzyme activity is U and it is 1 umol product per minute. There is a diagnostically important other unit called enzyme concentration and it is U/litre. Realy the only thing now is just to divide or multiply the answer with the powers of ten, or the conversion number between minute and second (if you are really lost it's 60 seconds in a minute. - srry for that )

Anyway hope I helped!
#4
March 4th, 2008, 04:50
 sootyandsweep Junior Member Join Date: Feb 2008 Posts: 3

Ah so simple! thanks for that. 6o seconds in a min lol :roll:
8)

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is Off Forum Rules
 Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home Science, Technology & Devices     General Discussion     Periodic Table     Organic Chemistry

All times are GMT -5. The time now is 00:00.