Calculating Net Charge on Proteins

[@anthonyg1111]

You are so blessed! for anyone that doesn't understand where some charges are from, amino groups, lysine, arginine, and histidine are type II ionization states which means when pH

[@MasayoMusic]

Thank you for clearing that up.

[@Gisei犠牲]

Yea man thanks

[@DerekLSmith-mr8pt]

I did not see your comment before I submitted mine, but it pertains to the same thing--that terminal NH3 in the protein starts out with a "+" at its pKa and COO starts out with "-" at its pKa. The other functional groups (-OH, -SH) are neutral at their respective pKas.

[@2DRichochet]

I've been looking for an explanation this simple and understandable all night. You were the light at the end of a 3 hours tunnel of googling stuff and failing to understand my professor's illegible notes. Thank youuuu 😭

[@Amaralivilava]

God bless you. thank you so much.

[@DerekLSmith-mr8pt]

The initial protein is drawn in the Zwitterionic form, and the terminal NH3 (2) and carboxylate (2) groups should be labeled with a "+" and "-," respectively. Otherwise, the logic behind the assignment of charges at the various pHs is vague.

[@semiramisyilmaz3693]

Dear Andrey, i passed my written and oral exam successfully! Lion's share is yours! millions of thanks... i feel very lucky to find your videos just in time. Keep up the good work.

[@AKLECTURES]

semiramis yilmaz congratulations! and thank you! :)

[@drewyoung7202]

IMMENSELY helpful. Thank you. I wish my biochem professor was this clear!

[@brandonjamison5403]

I wish you were a Professor and my school! You would be fantastic! Thanks for all of your help!!!

[@ania5038]

So basically... If the molecule has a negative charge, it will be NEUTRAL below or NEGATIVE above the pKa If the molecule has no charge, it will be NEUTRAL (i.e. 0) below or NEGATIVE above the pKa If the molecule has a positive charge, it will be POSITIVE below or NEUTRAL above the pKa

[@mayorstudland2929]

This helped in understanding part of my Biochemistry lesson in amino acids, thank you so much!

[@Gisei犠牲]

I study medicine in Turkey, although my class is Turkish, you tought me better then my Biochemistry teacher thanks

[@kikomartinez6121]

This video deserves more views and likes

[@ethanhunsaker9363]

I've been scouring youtube for a video that gives more precise measurements. for example if you are looking at what the charge of this poly peptide would be if the ph was 6.3. Effectively splitting charge given by histadine but by how much?

[@hasankuliyev4211]

In (A), why (OH) which you mentioned that has 0 charge cannot gain H and become + instead of being neutral since pH is 2?

[@peybak]

Maybe I am late, but the OH in carboxylic group can't gain an extra H and become positive in normal circumstances. For these groups, the charge can only be only neutral or a minus one. Same is true for cysteine and tyrosine. Nitrogens are opposite; they can only be positive or neutral under normal circumstances.

[@sahildhindsa8763]

how do you know the pka values of the molecules?

[@ramanavenkat7496]

Happy Teachers Day , I saw this just now , ur teaching is amazing ,.. I liked it 👍😁

[@joodii99]

We had the exact type of question on our exam and I got it wrong!! God I wish I've seen the video before my exam

[@Teeeheehaha]

This is such a well done video, thank you for helping me understand !

[@Lejonet120]

SUPER Thank you for that. I will donate when im finish mith me school and have a job. :)

[@한준성-i1i]

help me please why is the KIMKK do not move in electrophoresis at ph 11 (if N terminal's pka=9, R group of K's pka = 10 C terminal's pka =2) i think that the net charge is -1. is it right?

[@이호준-p6u]

We need to categorize catboxylic group and ammonia group when we calculate the net charge. Am I right?

[@nightgale71]

If there are 2 cysteines in the peptide and we want to see the net charge at say pH=9, do we consider -2 charge or will the 2 cysteines be involved in disulfide bond so that there is no charge contributed by them? please help, I am confused

[@M_h33]

Thanks you, you literally save my life ! I finally understand :)

[@haithamal-madhagi7769]

Prof, How do you put neutral charge on Tyr R, and positive charge on Lys R albeit 10.9 > 10.8 at pH of 2 and 5???

[@smrutiranjanrout6094]

why tyrosine becomes neutral charge 🤔🤔🤔🤔🤔🤔🤔🤔

[@lauraashley2933]

Late but replying in case anyone else is wondering - if O negative is protonated to OH, there's no charge, and the NH3+ and Coo- cancel out so that it an entirely neutral molecule

[@kingnyantz9839]

@@lauraashley2933 honestly I did struggle a bit to cope up with that so I only adapted to this only based on the fact of knowing amino acid I could treat special and one of those were Tyrosine, cysteine, glutamate and if you would wish to make me know another one's I could treat in the same way as to these I would appreciate

[@priyanka036]

Well explained sir but i need to ask a question that i have pka table and in that table pk1 value of cystein is 1.96 so acc. to that charge on peptide in 1st case is +2 is it correct

[@이호준-p6u]

Sir, I got question about (e)When you are finding the dirextly above pKa, why miss the 7.3(which si R group of Cystein)?I think (e) must be average of 7.3+6.0, 6.65 .Am I right?

[@RonnieTeeSmith]

It's 8.3, the glare on the board makes it hard to notice. So the value above & below pH 7 would be pka 8.0 & 6.0. [8 + 6 = 14 / 2 => pI of 7]

[@novembersveryown4350]

i think your pka values are a little off. overall concept is good though

[@antoniop.3972]

So useful, thank you very much!

[@arunkumars6257]

Thank you so much!

[@jakkirose6436]

So for histidine, I thought it could be positive, negative, OR neutral. It can have a +2, +1, 0, or -1 charge. Also, when would you use the Henderson - Hasselbolch equation?

[@tomharris6479]

Have you gotten an answer to this? Apparent can only be 0 or 1+ but I don’t understand why

[@jakkirose6436]

@@tomharris6479 hahaha I guess I never did get an answer on here. Thank you!!

[@tomharris6479]

@@jakkirose6436 I thought histidine could only have a +1 charge when it has a ph of below its pka of 6 and a 0 charge when is is deprotonated as it becomes neutral.

[@afc90501]

God bless you!

[@k.network8617]

This helped me so much!!! 🤓🤓❤

[@karolinadahlqvist4974]

Since tyrosine is protonated, shouldn't it have a charge of 0 at pH 2?

[@karolinadahlqvist4974]

I meant histidine!

[@marialaconi]

Shouldnt D be a net charge of -3? why is cys a negative charge?

[@Heidi-jz8ht]

At a pH of 11, cysteine will have a negative charge because the SH group will lose its H, making it S(-)

[@MrObaaad00]

why when ph was 5 tyrosin charge 0 though its pka is more than ph

[@Dannijay16]

I can't really see what you are doing...

[@AKLECTURES]

Dannijay16 Why not? Full screen + 1080 60p should do the trick. I

[@Dannijay16]

thank you... but i tried that... it still appears pretty tiny. But the content is very good. I was slightly confused by how you calculated the numbers though. I thought you just needed to compare pKa to pH, but your video made me realize that it is not always the case. I am preparing for the MCAT, but i never took biochem in college... can you provide me with a little more info on how to figure out what the charges are? Do you I need to memorize the acid side chains, pKa, and their trends at various pHs? I'm feeling a bit overwhelmed. Thank you. Danielle

[@haithamal-madhagi7769]

Prof, How do you put neutral charge on Tyr R, and positive charge on Lys R albeit 10.9 > 10.8 at pH of 2 and 5???

[@haithamal-madhagi7769]

Prof, How do you put neutral charge on Tyr R, and positive charge on Lys R albeit 10.9 > 10.8 at pH of 2 and 5???

[@haithamal-madhagi7769]

Prof, How do you put neutral charge on Tyr R, and positive charge on Lys R albeit 10.9 > 10.8 at pH of 2 and 5???

[@haithamal-madhagi7769]

Prof, How do you put neutral charge on Tyr R, and positive charge on Lys R albeit 10.9 > 10.8 at pH of 2 and 5???

[@BrockGrant]

Bit late to reply to your question, but essentially why it is a neutral charge is because with Tyrosines R group at a pH lower than 10.9, the hydroxyl group will remain protonated resulting in a neutral charge. However, if the pH is higher than this (i.e more basic), then tyrosine will LOSE its hydrogen, (OH --> O- + H+) and a -1 charge. I should also note that we are only looking at the R group because both the amino and carboxyl group are involved in the peptide bond and cannot be ionised. Hope that helps

[@haithamal-madhagi7769]

Prof, How do you put neutral charge on Tyr R, and positive charge on Lys R albeit 10.9 > 10.8 at pH of 2 and 5???

[@zellayqt1175]

SAME QUESTIONNN