I am jealous of your students! That is a beautiful explanation, thank you so much.

just watched 3 other vids trying to understand this, and this one helped me get it right away!

Thank you for solving my problem 😅

I watched so many vids about getting the charge of the peptide, and this video clearly explained it!! I can now answer my homework! thank you so mucchhhh

THIS PROF IS SO GOOD!!!! My prof explained only what PI was but I had no idea how to utilize in peptides. Thank you so much!

Short, simple and well explained. Great job :D

Thank you so much for this ! 😭

Gran video, mil graciasss

Thank you ma'am .

gurl u just saved my life

Thank you for this video! Your method really helped me understand the process!

@khayden777

4 жыл бұрын

Thank you! That is so great to hear! Good luck with your studies!

Thank you so much

thank you so much chegg just told me to only use two for a similar question without explaining why those two. but this literlitly explained why

@khayden777

4 жыл бұрын

So glad you found it helpful! Happy studies!

This is amazing....thanks Kate!!!!!

@khayden777

4 жыл бұрын

Thank you!

Thank you 😁

Thank you so much! The titration scheme is a helpful method. Could we also appreciate that she's writing mirror-inverted

@khayden777

4 жыл бұрын

Actually I am writing normally. I mirror flip the image when I edit the videos prior to publishing them :). However, I have also seen people record off physical mirror as well when making these videos.

I love you thank you

Where did the N-terminus 9.0 pKa come from? N group from Proline?

Thank you very much! I'm new to the subject. Can you recommend some good books to start with?

@khayden777

3 жыл бұрын

We use Foundamentals of Biochemistry by Voet Voet and Pratt in my class

@shashwatgaur7258

3 жыл бұрын

@@khayden777 I know I'm replying a tad bit later (my apologies), but thanks for the recommendation!

May I ask, what if an amino with an ionizable R group is repeated? So lets say two Lysines in a polypeptide?

@khayden777

Жыл бұрын

Hi Tae.. since both ionizable groups will be lost at the same pH, then you lose both charges (or gain both charges) when you cross their pKa. Their charges still add to the total (i.e. both will give a +1 so two lysines will give a +2.. but when you cross their pKa you lose both so go from +2 to 0... I hope that makes sense).

what if they give us three pKas for the basic/acidic aminoacids? which ones do we use for that specific aminoacid then?

@khayden777

3 жыл бұрын

For constructing your hypothetical titration: If it is a central amino acid, then you include the pKa of the R group as it is the only free ionizable group. If it is a terminal amino acid, then you include the pKa of the free terminus (whether it is the C or N end) and the pKa of the R group.

@asyareedus

3 жыл бұрын

@@khayden777 no i mean they give us 3 pKa s for each of the amino acids (central and terminal ones) and none for the COO or N terminus .. )obviously bc they already gave us the all pKas .. im sorry im german and ive been looking for this kind of exercises in german but couldnt find any and this is the first time im seeing the question being solved right

@khayden777

3 жыл бұрын

@@asyareedus ah, so you would follow my protocol, Ideally, you would be provided the N and C terminus pKa's. They don't fluctuate too much based on the identity of the peptide, so most instructors use 10 for the N terminus and 3 for the C. However, we know they do vary slightly... but it is a safe assumption especially if the isolecetric point exists between 2 R groups.

@asyareedus

3 жыл бұрын

@@khayden777 yes thank you, i ignored the low pH pkas that were given for the N terminus aminoacid and the otherway round for the C terminus.. (bc those were the ones for groups that were involved in the peptidbinding) thank you ur video rlly saved my exam :)

Ácids And bases have ionizable groups but polar and nonpolar don’t have

6:11 - I dont get this part ... HELP !!!!😪

Why not Ser? He has OH group...

@khayden777

3 жыл бұрын

Yes, but its pKa for the hydroxyl group is around 13. Typically much higher than biologically relevant, therefor most textbook authors put serine in the non-ionizable hydrophilic group of amino acids. That being said, there are plenty of enzyme mechanisms that rely on a coordinated effort of intermolecular interactions to deprotonate serine for covalent catalysis

@zexicc

3 жыл бұрын

@@khayden777 thanks

This is money