DeAdFX - 2-1-2006 at 21:45
I have found out that Urease greatly increases the hydrolysis of Urea in Ammonia and CO2.
On this msds for jack bean http://www.kikkoman.co.jp/bio/j/rinsyou/pdf/48_URE.pdf
It says that one unit of activity will produce 2 micro mols of ammonia per minute at optimal conditions and that speicific activity of this enzyme is
100U/mg.
Question: Does this "scale up" linearly say I had 500mg of this stuff hanging around in solution would I get 100 X 500 X 2 micro mol NH3 per minute
at optimum 100,000 micro mol of ammonia (or .1mol of ammonia a minute). Or is this wishful thinking.
Question: Would this be "economical" convert urea (your own/animal/industry) into NH3/CO2 for whatever the two are needed for. In my case see my odda
process question.
Question: The site also mentions heavy metals inhibit the reaction like K+ and Na+. Is it possible Li+ could help the reaction in the "right"
concentration?
Question: Catalyst maintaince. Is the time needed to watch the stuff justify the effort? Ie maintaing ph/temperature/chemical conc?
I have some more research tucked away in my favorites...
[Edited on 3-1-2006 by DeAdFX]
chemoleo - 2-1-2006 at 22:15
1) Yes, at optimal conditions you'd get that. Mind though, if you have less, then the enzyme just produces less proportionately, per minute. HOwever
you can't scale this up forever, you may get substrate or product inhibition (both which are subject to vast analyses in the literature). So it
depends on the enzyme. But at those low concentrations, I'm sure you can scale this up for a fair bit.
2) Whether it's economical or not, it depends on the price of urease compared to other industrial methods. For trials at home, it certainluy is
economical. You could even attempt to purify the urease yourself. I can help you on this, providing you got a source that contains a fair bit.
3) It is odd that they use K2HPO4 as a buffer, but yet they say it's an inhibitor. I don't think it's a very strong inhibitor. Otherwise, you can
always make a buffer with some other ions, i.e. Tris HCl or something. Li is likely to be better then, yes. Also note the temperature max activity is
at 60 deg C. You may not want that because you are likely going to inactivate protein. So I'd rather keep it at i.e. 30 deg C and save the protein.
4) There you have it, the main caveat. As the reaction proceeds in water, you will mainly get ammonium carbonate. So you won't have any gas bubbles
appearing reagardless. You'll just get an increasingly concentrated solution of (NH4)2CO3. This you can of course extract later by crystallisation.
Other than that, there isn't much to maintain - just check the ammonium carbonate doesnt change the ph significantly,
DeAdFX - 2-1-2006 at 22:32
Thank you for the quick response. I wanted a little of feed back because I am considering doing this or Bio Fuel(for hybrid rockets) after I am done
with another chemistry project (chemical oscillators).
My chemistry teacher would probably be willing to get my urease assuming I tell him what I use it for/ I pay for it (used up my "research money
budget" already)
As for now I can go to sleep with some confidence in this little thought of mine
.