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  2. How can I properly calculate the isoelectric point (pI) of amino acids? Related. 3. Isoelectric pH of ...

  3. biochemistry - How can I properly calculate the isoelectric point...

    chemistry.stackexchange.com/questions/136729/how-can-i-properly-calculate-the...

    Isoelectric point of an amino acid is the $\mathrm{pH}$ at which the molecule carries no net charge [1]. It can be calculated by the average of the relevant $\mathrm pK_\mathrm a$ values as you have mentioned. Your confusion seems to stem from choosing the relevant $\mathrm pK_\mathrm a$ values. For this we should refer to the titration curve ...

  4. For this, you can use the Henderson-Hasselbalch equation.Using the degree of dissociation, $\alpha$, this can be written as $$\mathrm{pH} = \mathrm{p}K_\mathrm{a} + \log\frac{\alpha}{1- \alpha}$$ Rewriting to solve for $\alpha$: $$\alpha = \frac{1}{10^{\mathrm{p}K_\mathrm{a} - \mathrm{pH}} + 1}$$ As stated above, $\alpha$ is the degree of dissociation, meaning the degree at which $\ce{H+}$ is ...

  5. Why and when is lysine charged - Chemistry Stack Exchange

    chemistry.stackexchange.com/questions/24727

    If the pH = pI you have a zwitterion with on positive and one negative charge, so the whole molecule is neutral. If your pH is higher than the pI it is mor basic and something will deprotonate so you have a negative charge. If pH < pI something is protonated und you have a positive charge. pI refers to that point there half of all

  6. What's the difference between isoionic point and isoelectric...

    chemistry.stackexchange.com/questions/95377

    The isoionic point is defined as the point at which dissociable groups of the substance combine equally and only, with hydrogen and hydroxyl ions [6]. This is identical with the isoelectric point only when the substance does not combine with ions other than hydrogen or hydroxyl.

  7. Isoelectric Point - Chemistry Stack Exchange

    chemistry.stackexchange.com/questions/180365/isoelectric-point

    The isoelectric point is the pH at which the amino acid is in its zwitterionic form (neutral, typically with a deprotonated carboxylic group and a protonated amino group). The titration of an amino acid is similar as the titration of a diprotic weak acid, with 2 buffer regions at pH=3 and pH=9 (which correspond to the pKa of the alpha ...

  8. Applying Henderson–Hasselbalch equation to amino acids: which pKa...

    chemistry.stackexchange.com/questions/61624/applying-henderson-hasselbalch...

    I was wondering which $\mathrm{p}K_\mathrm{a}$ to use when calculating the ratio of $\ce{HZ}$ to $\ce{Z-}$ of amino acids, the Henderson–Hasselbalch formula used: $$\mathrm{pH} = \mathrm{p}K_\text...

  9. In our biochemistry class we were introduced to a rule of thumb, which goes something like this: "If the pH of a solution is one or more units below the $\\mathrm{p}K_\\mathrm{a}$ of a group, then ...

  10. How to determine the charge of amino acid at certain pH?

    chemistry.stackexchange.com/questions/170512/how-to-determine-the-charge-of...

    Problem What would charge would you expect on alanine when placed in a solution with a pH of 1.00? Answer Question Let's say I am given a certain pH of 2.00 rather than 1.00 for the &quot;acidic

  11. biochemistry - How do I calculate the ensemble-average net charge...

    chemistry.stackexchange.com/questions/119920/how-do-i-calculate-the-ensemble...

    Not just the charge of each side chain or N/C-terminus-- the sum of all groups. Everywhere else on the internet, I had only been able to find an average/rounded charge. I needed to know, to a decimal's point, what the charge of amino acid is at a certain pH when 1 or more groups has a partial charge. $\endgroup$ –