Enzymes, Amino acids, Polypeptides!

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oviav
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Enzymes, Amino acids, Polypeptides!

Post by oviav » Mon Oct 19, 2009 6:31 pm

Right... I have a few question to ask. I sort of missed all if not most of these topics in class due to illness. So I'm just looking for explanations of how you come to answer! :(

For this question its basd on how lactose-reduced milk is formed in an industrial reactor using the enzyme lactase.
Questions asks: In terms of the way which enzymes work, explain why it is necessary to pass the milk through the reactor several times to reduce the amount of lactose sufficiently.
I have no idea why. Nothing in the Biology Text book ! :(

The others are based upon a Polypeptide chain, in the sequence of:

Lys(cut here by tryp)-Val-Arg(here by tryp)-Ser-Lys(here by tryp)-Ala-Phe(here by chym)-Val-Trp(here by chrym)-Ile-Ile-Glu-Val-Pro-Lys(Tryp here too)

Then it asks: How many amino acid fragments will be produced from this polypeptide if it is incubated with a mixture of trypsin and v8 protease. ok just foudn out chymotrypsin breaks up tyr,try, and phe.

therefore is it 6 0.0??


ii) Explain why trypsin and chymotrypsin break peptide bonds betwen amino acids.

Is this because it Hydrolysises the proteins? I know Trypsin sort of breaks peptide chains at the carboxyl side of the amino acids lysine or arginine!But no idea about chymotrypsin. Never heard of it. :(


iii) Describe how you would use a biochemical test to shoe a solution contained protein.

I don't know if its Benedic's or Biuret. Biuret maybe? :? So Sugars with Benedict's solution. Protein with Biuret ??

oviav
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Post by oviav » Mon Oct 19, 2009 8:40 pm

Anyone out there willing to give me some hints? ;(

Just need to get through these questions, and revise. -.-"

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JackBean
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Re: Enzymes, Amino acids, Polypeptides!

Post by JackBean » Mon Oct 19, 2009 10:30 pm

Give it some time :roll: We have to sllep some time also :evil:

1) Look at the enzymatic kinetics. The reaction is not linear going to zero.

2) http://www.lmgtfy.com/?q=v8+protease
Let you try to count once again ;)

3) http://www.lmgtfy.com/?q=chymotrypsin
here you have the mechanism:
http://www.mpcfaculty.net/mark_bishop/chymotrypsin.htm

4) http://www.lmgtfy.com/?q=protein+determination
(just two first links give you best answer ;) )
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

oviav
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Post by oviav » Tue Oct 20, 2009 12:05 am

1) Aww man, still not "getting" this. >-<

2) Silly me, mixed up with chymotrypsin and v8 protease! So it's 5? :)

3) So to do with active sites and substrates :S

4) I guess Biuret is the one!!

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