Protein Reaction Lab Report
If pH > pI, then the protein will have a negative charge and if pH < pI, the protein will have a positive charge. Buffer I has a pH >5, meaning both proteins carry a negative charge and bind to the DEAE (a positively charged resin).
(b) pH = pKa + log10(Base/Acid) [Base = mM of sodium acetate; Acid = mM of acetic acid] = 4.7 + log10 (40/40) = 4.7
In order for the catalase to elute from the column, it must have lost its negative charge and stopped binding to the DEAE. Lowering the pH nullifies the negative charge on the protein molecules. The pH of Buffer II is 4.7, which is < pI, the protein will be positively charged. This caused catalase to stop binding to DEAE and elute from the column. Because the pH of Buffer II > pI of glucose …show more content…
A hydrophobic column will elute the most hydrophobic compound last. Methionine is more hydrophobic than Arginine however, due to the lack of polarity in Methionine and the strong pos. charge of Arginine, Methionine is eluted first.
(c) Glu and Val
(i) Glutamic acid and Valine.
(ii) Glutamic acid will elute first.
Acids with greater negative charges have a small pKa, and are subject to a larger effect from electrostatic forces than acids with more positive charges. Therefore organic acids elute in order of pKa size, starting with the smallest pKa values. Valine has a higher pKa than Glutamic acid, which means Glutamic acid is eluted off first due to this smaller pKa size.
Charge of Glutamic acid at pH 7 = -1. SO3- is negatively charged and will bind to pos. charged proteins strongly, so the protein that is more pos. charged will bind strongest and elute last on the column; in this case, Valine.
The polystyrene resin has a strongly hydrophobic backbone. A hydrophobic column will elute the most hydrophobic compound last. Valine is more hydrophobic than Glutamic acid, so it is eluted last.
BY2201 PRACTICAL 3 Kinetics
(a)
(i) Amount of product formed/ unit time = rate of
(b) pH = pKa + log10(Base/Acid) [Base = mM of sodium acetate; Acid = mM of acetic acid] = 4.7 + log10 (40/40) = 4.7
In order for the catalase to elute from the column, it must have lost its negative charge and stopped binding to the DEAE. Lowering the pH nullifies the negative charge on the protein molecules. The pH of Buffer II is 4.7, which is < pI, the protein will be positively charged. This caused catalase to stop binding to DEAE and elute from the column. Because the pH of Buffer II > pI of glucose …show more content…
A hydrophobic column will elute the most hydrophobic compound last. Methionine is more hydrophobic than Arginine however, due to the lack of polarity in Methionine and the strong pos. charge of Arginine, Methionine is eluted first.
(c) Glu and Val
(i) Glutamic acid and Valine.
(ii) Glutamic acid will elute first.
Acids with greater negative charges have a small pKa, and are subject to a larger effect from electrostatic forces than acids with more positive charges. Therefore organic acids elute in order of pKa size, starting with the smallest pKa values. Valine has a higher pKa than Glutamic acid, which means Glutamic acid is eluted off first due to this smaller pKa size.
Charge of Glutamic acid at pH 7 = -1. SO3- is negatively charged and will bind to pos. charged proteins strongly, so the protein that is more pos. charged will bind strongest and elute last on the column; in this case, Valine.
The polystyrene resin has a strongly hydrophobic backbone. A hydrophobic column will elute the most hydrophobic compound last. Valine is more hydrophobic than Glutamic acid, so it is eluted last.
BY2201 PRACTICAL 3 Kinetics
(a)
(i) Amount of product formed/ unit time = rate of