SDS disrupts noncovalent bonds like...

[SaintJude]

SDS gel electrophoresis disrupts all noncovalent interactions in a protein. So that means it will keep the peptide bond intact right?

Below is a structure of a protein. Which bonds will SDS disrupt?

---

Members don't see this ad.

 

[EnginrTheFuture]

SDS gel electrophoresis disrupts all noncovalent interactions in a protein. So that means it will keep the peptide bond intact right?

Below is a structure of a protein. Which bonds will SDS disrupt?

It disrupts secondary and tertiary structure but NOT disulfide bridges I believe...

I for some reason remember it not effecting H-bonding but that wouldn't make sense because isn't secondary structure based on essentially H-bonding only?

 

[SaintJude]

Hmm. thanks. Well, secondary structure is primarily due to intramolecular hydrogen bonding between nearby amino acids. So perhaps SDS does affect H bonds and thereby disrupts the secondary structure?

About tertiary structure, that's mostly determined by interaction b/w R-groups of amino acids and disulfide bonds. So maybe SDS then affects the interactions b/w R-groups?

It makes sense that disulfide bonds are not affected, b/c disulfide bonds are covalent.

 

[MDschoolorbust]

SDS only affects secondary and above except disulfide bonds. All other bonds are H-bonds and are thusly denatured. I think. This is from chapter 1 of EK Bio right?

 

[MedPR]

Pretty sure the point of SDS is to break all bonds other than primary structure in order to make the charge of every single protein the same. Thus proteins are then separated by weight regardless of their natural charge.

So H-bonds, hydrophobic interactions, and ionic interactions.

 

[typicalindian]

Yeah basically SDS converts all the peptides into their primary structures (so to answer your question, the peptide bonds are still in tact) and gives them a negative charge. Then when you run the gel you separate the peptide fragments by size with the smaller fragments being the furthest down on the gel.

 

[Morsetlis]

Pretty sure the point of SDS is to break all bonds other than primary structure in order to make the charge of every single protein the same. Thus proteins are then separated by weight regardless of their natural charge.

So H-bonds, hydrophobic interactions, and ionic interactions.

Correct.

Fun fact: Making an SDS solution from powder in the lab = FUN BUBBLE TIME

 

[MDschoolorbust]

correct.

Fun fact: Making an sds solution from powder in the lab = fun bubble time

fun bubble time?!?!

 

[red doctober]

If my memory serves me correctly from biochem lab, mercaptoethanol with heating is used in SDS-PAGE to reduce the disulfides so that only the primary structure remains. In addition to disrupting the non-covalent interactions, SDS coats the proteins proportionally to their size and therefore the rates at which the proteins travel in the gel are relative to their sizes. SDS is negatively charged and accelerates in an electric field toward the anode, which is what mainly causes the proteins to move.

 

[Morsetlis]

If my memory serves me correctly from biochem lab, mercaptoethanol with heating is used in SDS-PAGE to reduce the disulfides so that only the primary structure remains. In addition to disrupting the non-covalent interactions, SDS coats the proteins proportionally to their size and therefore the rates at which the proteins travel in the gel are relative to their sizes. SDS is negatively charged and accelerates in an electric field toward the anode, which is what mainly causes the proteins to move.

Correct.

Now tell me what mercaptoethanol smells like.

 

[red doctober]

Correct.

Now tell me what mercaptoethanol smells like.

Burnt hair