This video will discuss the basics for calculating the net charge of amino acids and polypeptides. This will provide a structure for calculating pI (isoelectric point) as well.
I always believed that there are people who have a talent to explain complicated concepts and those who do not. Unfortunately many professors and TAs, mine included, do not know how to teach. You are doing a great job! Keep it up!
I am in 2nd year biochemistry at my uni and ive learned more in this video than i have all semester so far. I really needed someone to simplify the basics and you did!! And with such a soothing voice!! I want to be tutored by you! Thank you so much !
Thank you so much for teaching me this information so clearly! 😊 I have a final exam and was stuck on the zwitterion concept in pH of 7, but now I understand it because of your examples. Many thanks!
In my class, my professor said that if the pH is more than 2 units above or below the pKa, we had to use the H-H equation because we need to solve to the nearest 0.01 for net charge. I honestly hate using that thing. I wish he'd let us do what this guy did in the video because it makes so much more sense to me.
The arg at a pH at 11 should be neutral. If you have an NH3+ then deprotonate the net charge should be 0. What I liked is that you explained the "exceptions" to the rules. Like cys with the SH group. Lys and Arg with the NH3+, lastly His with the NH+. I think this is the part that most professors don't explain. EXCELLENT JOB!
my professor showed us the table then told us when phpka then its negative next class session he wanted us to know this shit already without once going through it like wtf! Thanks for explaining
This was great! 2 questions: 1. My biochem book lists the amino/carbox terminals as NH3+ and COO- instead of NH2 and COOH, and it affects the overall charges. Which is correct? 2. What if the pH is equal to pKa? What is the charge then?
Maan where were you back in early 2012 when I was taking structural Biochem. . . Taking protein science now, so it's still a nice revision video. Thanks!
It depends if your instructor will allow you to use a chart on your tests. My instructor required us to memorize all the pKa's. Sounds tough but there are only 9 numbers to memorize.
Hello, Sir. I have a question for you. What happens if the pH of the solution is equal to the pK of one of the amino acids? For example, the overall pH is 8.4, and there's cysteine, which has pK=8.4. What would be the charge of cysteine? I can't seem to find an answer to that question anywhere.
aren't you using the pKa of the R-group rather than the pI to find the pI of the whole protein? I mean the assumption is that the peptide bond (O=C-N-H) is neutral right?
Thank you, this was useful but I am still wondering why some sites are saying that at pH 5 Glycine has a net charge of +1? I wanted to say it had no net charge but what about the H+ ion is that not technically Glycine's R group?
I tried it out, but I didn't get the same answers. I mean wouldn't the pKa's of the COOH and NH3+ groups be different from the COO- and NH2 groups, therefore affecting overall charge?
Ammonia doesn't have a plus 1 charge. If you put NH3 in solution it will be protonated to form NH4+. Nitrogen has a valence of 3, therefore it carries no charge when it is covalently bonded to three different groups. You need to change this.
I always believed that there are people who have a talent to explain complicated concepts and those who do not. Unfortunately many professors and TAs, mine included, do not know how to teach. You are doing a great job! Keep it up!
This is by far, THE best video on TH-cam about explaining amino acids and their charge! Thank you so much!
I am in 2nd year biochemistry at my uni and ive learned more in this video than i have all semester so far. I really needed someone to simplify the basics and you did!! And with such a soothing voice!! I want to be tutored by you! Thank you so much !
This is the only video I have found after extensive searching that explains this so simply!! Thank you so much all the way from Tasmania, Australia!
This was SO helpful. Cannot stress it enough. Thank you so much for this.
This is the best explination I've had on this subject! Thank you so much.
Finally after months of searching!! Big thumbs up my friend. Thank you so much!
The BEST explanation! Thank you from Greece!
Thank you so much! Your video is the only video that explained the concept of the peptides throughly.
Great explanation! Thank you! I've watched many videos. Yours helped me the most.
Wow! So many of my friends couldn't explain it to me, you did in just 20mins! Thank you! Keep doing this type of videos!
thank you for saving me hours of pain and suffering
This video really just saved me from my frustration. Thank you so much. I wish you had more videos!
The BEST explanation! Thank you from Pakistan!
WOW. This was the MOST helpful. I'm incredibly grateful. Thank you for your help!
Thank you so much for taking the time to make this. Incredibly helpful!
Your video has helped me out big time! Thanks a lot for sharing the knowledge.
I never thought is was so much to understand about Amino Acids
Thank you so much for teaching me this information so clearly! 😊 I have a final exam and was stuck on the zwitterion concept in pH of 7, but now I understand it because of your examples. Many thanks!
Best explanation I've found, thank you.
Wow, this is so greatly explained. My searching is over!! Thank you very much :)
You explain this SO WELL! Thank you, thank you, thank you :D Make more videos please; you're really good at breaking things down!!!
Thank you for taking the time to explain this. it was really helpful.
How do you know if something can't depronate any further and if the charge of a group is zero by looking at the table
In my class, my professor said that if the pH is more than 2 units above or below the pKa, we had to use the H-H equation because we need to solve to the nearest 0.01 for net charge. I honestly hate using that thing. I wish he'd let us do what this guy did in the video because it makes so much more sense to me.
The arg at a pH at 11 should be neutral. If you have an NH3+ then deprotonate the net charge should be 0. What I liked is that you explained the "exceptions" to the rules. Like cys with the SH group. Lys and Arg with the NH3+, lastly His with the NH+. I think this is the part that most professors don't explain. EXCELLENT JOB!
wow way better than my biochem prof
You, sir, are a life saver!
my professor showed us the table then told us when phpka then its negative next class session he wanted us to know this shit already without once going through it like wtf! Thanks for explaining
Wow, you made it so much easier to understand. Thank you :D
this is some big brain stuff, thanks sir!
Great Video ! Thanks a lot. The table works pretty good.
This was great! 2 questions:
1. My biochem book lists the amino/carbox terminals as NH3+ and COO- instead of NH2 and COOH, and it affects the overall charges. Which is correct?
2. What if the pH is equal to pKa? What is the charge then?
Best explanation of this concept....Thanks
This is biochemistry explained very efficiently!
You're a great teacher!
Maan where were you back in early 2012 when I was taking structural Biochem. . . Taking protein science now, so it's still a nice revision video. Thanks!
i feel at ease right now..thank you
Thank u very much I finally understand net charge I use to think it was hard and confusing but now I can do it
its the chart at 5:05 that wasnt emphasized in my lectures and might be what is confusing you guys when calculating for charge. Thank u!1
thank you so much, your teaching method is great :) you helped me a lot, thanks again :)
Please make more videos! This was so good!
This video helped a lot. Thank you!
Very nice explanation, thanks a lot!
You, sir, are awesome! Thanks so much
Very Helpful!! Thanks so much!!
you are just wonderful. God bless you
Very clear and simple thank you!
Why am I so relieved to finally find a TH-cam video that wasn't made by a foreign guy? They're mostly Indian, so annoying. Thanks for the video JD
Nice explanation!
this was amazing. thank you so much!
Thank you so much! This was very helpful
Thank you so much for this great video.
So helpful! Thank you
At 11:39...does anyone know where the values at the terminal ends of the peptide chain are coming from.?
Thank you..it helps me a lot
Great explanation. Thank you.
you my friend are amazing, thank you
So helpful - thanks so much!
Great Video!
thank you so much, this vid is really helpful
It depends if your instructor will allow you to use a chart on your tests. My instructor required us to memorize all the pKa's. Sounds tough but there are only 9 numbers to memorize.
thanks a lot. this helped a lot. please upload more helpful videos
Thank you so much ! This is really helpful ^^
U have confused me
.so don't upload these confusing videos
Hello, Sir. I have a question for you. What happens if the pH of the solution is equal to the pK of one of the amino acids? For example, the overall pH is 8.4, and there's cysteine, which has pK=8.4. What would be the charge of cysteine? I can't seem to find an answer to that question anywhere.
The side chain wouldn't react. The amino and carboxyl groups are the ones that would react. I think it gives a net charge of zero(NH3+ and COO-)
It means you have half at the protonated form and half deprotonated, it would be -.5 charge.
The protonated and deprotonated forms are in a 50/50 eqm.
How do we determine the net charge if we don't have access to that nice chart?
you sir are a life saver. thank you.
this really helps! Thank you!
aren't you using the pKa of the R-group rather than the pI to find the pI of the whole protein? I mean the assumption is that the peptide bond (O=C-N-H) is neutral right?
Thanks, this really helped!
very helpful, thank you
THANKS, I finally got it !!!!!
Isn't the NH2 from Serine and the COOH from Histidine? Why don't we calculate the net charge of Histidine as being 6 + 3.1?
Thank you, this was useful but I am still wondering why some sites are saying that at pH 5 Glycine has a net charge of +1? I wanted to say it had no net charge but what about the H+ ion is that not technically Glycine's R group?
Oh also what about when the pKa is the same as the pH would it be 50/50?
very clear, thank you!
I tried it out, but I didn't get the same answers. I mean wouldn't the pKa's of the COOH and NH3+ groups be different from the COO- and NH2 groups, therefore affecting overall charge?
Expanding upon my earlier point, you notice amino group on glycine having three bonds with no charge. This structure is correct.
Well explained Sir tqsm Sir
if you test it at pH=8, then what is the charge for the N-terminus?
I have to come back on this ... 👍🏼
Isnt lysine at ph12 supposed to have a net charge of -1?
2. If the pH is the same as the pKa, the charge is zero/no charge.
Thank you sooooo much!!!!!!!!!!
very good. Thank you!
Thank you so much! awesome accent as well :3
Yeah, I noticed that as I was working through some problems. We ended up not having to even calculate charge anyway on our test, so it doesn't matter.
THANK YOU SOOOOO MUCH!
Thank you based god
thank you! this helped a lot :-)
really helpfull ! thankx ;)
THANK YOU
Ammonia doesn't have a plus 1 charge. If you put NH3 in solution it will be protonated to form NH4+. Nitrogen has a valence of 3, therefore it carries no charge when it is covalently bonded to three different groups. You need to change this.
Thank you!!
Thank you!
thank you so much!
you the man
Are you from Texas
thanks billy
He's talking about them as a substituent. -NH3+ is what he means, not an ammonia by themselves; since we are talking about amino acids.
Thank you!!!