How does hydrochoric acid denature proteins?

Is it something to do with the pH? And what effect does an increased concentration have?

Also is this the same with other acids?

Reply 1

Eloades11

17

Different proteins work at different optimal pH conditions. In general, the addition of HCl to proteins causes an irreversible conformational change by disrupting the bonding of peptides, thus disrupting the catalytic domains. This will also happen if you add other acids to proteins (unless of course the proteins typically function under acidic conditions).

Reply 2

Tj789

OP

10

Original post by Eloades11

Different proteins work at different optimal pH conditions. In general, the addition of HCl to proteins causes an irreversible conformational change by disrupting the bonding of peptides, thus disrupting the catalytic domains. This will also happen if you add other acids to proteins (unless of course the proteins typically function under acidic conditions).

I dont understand. Tomorrow im doing an experiment which is about precipitating plasma proteins out of a solution (HCL) and one question I think "explain why HCL is a disadvantage when precipitating proteins." Well I thought its because hcl has a lower pH which means the enzyme denatures as its not at optimum any longer... oh and by this "irreversible confrontational change" is that denaturing" and by this peptide bonds you mean amino acids? Please dumb it down for me

Reply 3

Eloades11

17

Original post by Tj789

I dont understand. Tomorrow im doing an experiment which is about precipitating plasma proteins out of a solution (HCL) and one question I think "explain why HCL is a disadvantage when precipitating proteins." Well I thought its because hcl has a lower pH which means the enzyme denatures as its not at optimum any longer... oh and by this "irreversible confrontational change" is that denaturing" and by this peptide bonds you mean amino acids? Please dumb it down for me

I'm not sure what context you're referring to for your experiment (I doubt your protein will be stored in HCl), but yes HCl will most likely denature your protein. Conformational change just mean the protein will change shape, while you should know that most proteins become non-functional when this happens (but not all the time).

Amino acid is another word for peptide, so peptide bond is the bond which connects 2 amino acids together.

Reply 4

Kallisto

Entertainment Forum Helper

22

Original post by Tj789

Is it something to do with the pH? And what effect does an increased concentration have?

Also is this the same with other acids?

Before I give an answer, look at this picture:

http://alevelnotes.com/content_images/Image85.gif

Do you see the ionic bond between the sturcture of a protein? do you see the two different charges between them too? these different charges hold the structure together. Acids in general are proton donors, that is to say they 'release' protons. Protons have positive charges, but I suppose its known by yourself. Whenever a proton is donated, the negative charge of the ionic bond, the carboxylate-ion (COO-) is attracted by the positive charge. So it comes to a reaction between this negative charge of the ionic bond and the positive one of the proton, a carboxyl group (COOH) comes into being. Under these circumstances the ionic bond is not able to hold the structure of the protein together, just because the carboxylate group has a neutral charge. So the protein structure begins to denature, the active center is changed and the substrate cannot be catalysed by enzymes (enzymes are proteins, do you know?).

In terms of pH its to say, the greater the value, the stronger the acid. Acids with higher values are greater in trying to donate protons. I guess you can image for yourself what that means? the best pH value is between 7-8, that is quasi the neutral area of a liquid. Values below it have the contrary effect compared to acids. Values below the neutral area are bases, they work alkaline, that is to say they are proton acceptor, they take ones.

(edited 9 years ago)

How does hydrochoric acid denature proteins?

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