Denaturation and Digestion

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Denaturation and Digestion

Green Xenon
Hi:

When a protein denatures, it loses its non-covalent bonds and gains
covalent bonds. Aren't covalent bonds more difficult to break than
non-covalent bonds? If so, how does denaturing a protein help digest it
into amino acids?


Thanks,

Radium

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Re: Denaturation and Digestion

Green Xenon

DK wrote:

> In article <[hidden email]>, "Radium" <[hidden email]> wrote:
> >Hi:
> >
> >When a protein denatures, it loses its non-covalent bonds
>
> Yes, roughly speaking.
>
> >and gains covalent bonds.
>
> No, generally not true.

Don't boiled eggs harden due the formation of covalent bonds?

http://science.howstuffworks.com/question616.htm

"As the temperature increases, the proteins gain enough energy to form
new, stronger bonds (covalent) with other protein molecules."

"As the proteins form these new, strong bonds, the water that
surrounded each protein molecule when the egg was liquid is forced
out."

> >Aren't covalent bonds more difficult to break than
> >non-covalent bonds? If so, how does denaturing a protein help digest it
> >into amino acids?
>
> By opening up its "core" and making it more accessible to the
> digestive enzymes.

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Re: Denaturation and Digestion

Green Xenon
DK wrote:

> Few disulfide bridges do indeed form randomly but this contributes
> essentially nothing to the aggregation/gelation and most definitely
> is not relevant to a general phenomenon of protein denaturation.
> (Heat or any other)

What causes these disulfide bridges to form?

Also, is it possible to thermally-denature a protein w/out causing it
to coagulate?

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Re: Denaturation and Digestion

Dr Engelbert Buxbaum
Radium wrote:

> Also, is it possible to thermally-denature a protein w/out causing it
> to coagulate?

Such experiemnts were performed with barnase and ribonuclease. Boil to
denature (loss of enzymatic activity), cool to renaturate.

Denaturation means the opening of tertiary and secondary protein
stucture, coagulation the uncontrolled association of proteins. In
normal proteins hydrophobic parts are burrried inside, hydrophilic parts
are on the surface. Once this structure is lost, hydrophobic sites are
exposed, leading to uncontrolled association by hydrophobic
interactions.
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