What is the Isoelectric points of amino acids?

Isoelectric point (pI): The hydrogen ion concentration at which a particular amino acid does not influence by electric field is known as Iso-electric point (pI).

At isoelectric points:

(1) [cation] = [Anion]

(2) Net charge on particular amino acid is zero.

(3) Maximum concentration of zwiter ion

(1) Isoelectric point (pI) of neutral amino acid (for example alanine) is the average of pKa1 and pKa2. For example pI of alanine calculated as:

          PI= 1/2(pKa1+pKa2)

(2) Isoelectric point (pI) of acidic amino acid is the average of pKa values of two -COOH groups (uncharged) in its acidic form. For example pI of Glutamic acid calculated as:

(3)Isoelectric point (pI) of basic amino acid is the average of pKa values of two positively charged amine groups in its acidic form. For example pI of lysine calculated as:

Notes: Acidic amino acid has lowest pI value while basic amino acid had highest isoelectric point (pI).

Related topic:

Amphoteric salt hydrolysis:

How to calculate Isoelectric point (pI) of acidic and basic amino acids?

Isoelectric point (pI): The hydrogen ion concentration at which a particular amino acid does not influence by electric field is known as Iso-electric point (pI).

At isoelectric points:

(1) [cation] = [Anion]

(2) Net charge on particular amino acid is zero.

(3) Maximum concentration of zwiter ion

(1) Isoelectric point (pI) of neutral amino acid (for example alanine) is the average of pKa1 and pKa2. For example pI of alanine calculated as:

          PI= 1/2(pKa1+pKa2)

(2) Isoelectric point (pI) of acidic amino acid is the average of pKa values of two -COOH groups (uncharged) in its acidic form. For example pI of Glutamic acid calculated as:

(3)Isoelectric point (pI) of basic amino acid is the average of pKa values of two positively charged amine groups in its acidic form. For example pI of lysine calculated as:

Related topic:

Amphoteric salt hydrolysis:

50 ml of C3H8 is mixed with 300 ml of oxygen for complete combustion find out the final volume and volume concentration.

 

Related Questions:

(1) 1 ml of gaseous aliphatic compound CnH3nOm is completely burnt in an excess of O2 and cooled to room temperature. The contraction in volume is..

(2) 1 ml of gaseous aliphatic compound CxHyOz is completely burnt in an excess of O2 and cooled to room temperature. The contraction in volume is..

The maximum number of hydrogen bonds formed by a water molecule in ice is.

 

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What is "Nascent" Hydrogen ?

How many gram Cu will deposited by passing 2 Amp for 30 minutes in aq solution of CuSO4. What will be weight of O2 produced at anode?

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(1) A current of 2.68 ampere is passed for one hour through an aqueous solution of copper sulphate using copper electrodes. Calculate the change in the mass cathode and that of anode. ( atomic mass of copper is 63.5 u).

(2) In the electrolysis of aqueous solution of NaOH , 2.8 litre of oxygen at NTP liberated at anode. How much Hydrogen was liberated at cathode ?

(3) On passing 3 faradays of electricity through three electrolytic cells connect in series containing Ag+ , Ca+2 and Al+3 ions respectively , the molar ratio in which three metals ions are liberated at the electrode is

(4) How many grams of silver could be plated out on a serving tray by electrolysis of solution containing silver in +1 oxidation state for a period of 8 hours. At a current of 8.46 ampere? What is the area of tray if the thickness of silver plating is 0.00254 cm. density of silver is 10.5 gm cc.

(5) A current of 3 ampere passed for 2 hours through a solution of CuSO4 3 gm of Cu2+ ions were discharged at cathode calculate the current efficiency.

(6) What current strength ampere will be require to liberate 10 gm chlorine from sodium chloride solution in one hour?

(7) Ag is electrodeposited on a vessel of total surface area 800 cm2 by passing current of 0.2 A for 3 hrs. Calculate thickness of Ag deposited. (Density Ag = 9.67 g/ml).

(8) 0.5 faraday of electricity was passed to deposit all the copper present in 500 ml of CuSO4 solution. What was the Molarity of this solution?

(9) How long has a current of 3 ampere to be applied through a solution of silver nitrate to coat a metal surface of 80 cm2 with 0.005 cm thick layer density of silver is 10.5g/cm3.

(10) 1 M aqueous solution of NaCl undergo electrolysis if 50 mA current is passed for 12 hours assume current efficiency is 25%. The total volume of gas produced at standard state is. NaCl (aq) solution undergoes electrolysis as:

(11) Zn amalgam is prepared by electrolysis of aqueous ZnCl2 using 9 gram Hg cathode. How much current is to be passed through ZnCl2 solution for 1000 seconds to prepare of Zn amalgam with 20% weight? (Atomic wt, Zn = 65.4 g)

(12) During electro refining of Cu how much time is needed to produce 250g Cu on the cathode if the current is kept at 11 A?

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