help please!

Frank Fürst ffrank at rz.uni-potsdam.de
Wed Jan 30 07:40:10 EST 2002


mmuurrttuuzzaa at hotmail.com (Azutrum) schrieb:

> Hi, 
> 
>   Can anyone please explain what is proteolysis. I looked it up and
> all I understand is that it is the hydrolysis of proteins which causes
> them to break down. Is this correct or not? If it is not please tell
> me what it is?

It is. Usually it is implied that the hydrolysis reaction is catalyzed
by an enzyme. It may be unspecific (e.g. an exopeptidase just removing
amino acids from the terminus, one by one) or specific, i.e. the enzyme
looks for a particular amino acid sequence on the polypeptide chain and
cleaves at a specific point in this sequence.

>    Also please explain what is the " Ka-Mg2+ ". My understanding is
> that ka is the acid dissociation constant. But I thought that applied
> to acid which gain electron. But how does it apply to Mg2+. If I am
> totally wrong please explain what it may be.

I don't know. Could you indicate indices and superscripts, like
K_a^{Mg2+} or the like? Perhaps it is just the association constant for
Magnesium: 

          c(enzyme*Mg2+)
K_a = -----------------------
        c(enzyme)  c(Mg2+)}

> I am reading an article on Allosteric inhibition of
> Fructose-1,6-bisphosphate

must be an enzyme. Phosphofructokinase?

HTH, Frank




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