QUESTION: What are the buffer regions/effective pH range?
Nucleotides
It is an organic molecule made up of three basic components- a nitrogenous base, phosphate,and pentose sugar. The nucleotides are important for metabolic reactions andthe formation of DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
Nucleic Acids
Nucleic acids are essential biomolecules present in prokaryotic and eukaryotic cells and viruses. They carry the genetic information for the synthesis of proteins and cellular replication. The nucleic acids are of two types: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). The structure of all proteins and ultimately every biomolecule and cellular component is a product of information encoded in the sequence of nucleic acids. Parts of a DNA molecule containing the information needed to synthesize a protein or an RNA are genes. Nucleic acids can store and transmit genetic information from one generation to the next, fundamental to any life form.
The ideal buffer range for any amino acids is pH above or below its pI values because the amino acid will get get precipitated at its pI.
pKa1 of -COOH group of Cys = 1.71
pKa2 of -NH2 group of Cys = 10.78
pKa3 of side chain group of Cys = 8.33 (it indicates that the thiol group of Cys is a strong acid than the -NH2 group pf Cys as pKa Cys side chain is lower).
Thiol side chain of Cys will loose proton first than -NH2.
Net charge on Cys is zero in structure B, i.e. Structure B is a zwitterion and pI can be calculated from pKa1 and pKa3.
Structure B of Cys, pI = (8.33 + 1.71) / 2 = 10.04/2 = 5.02
pH above its pI the Cys will be -vely charged (deprotonated) while pH below its pI it will be +vely charged (protonated).
So, selection of buffer depends on its pI values, not pKa values of each functional group,
QUESTION: What are the buffer regions/effective pH range?
Step by step
Solved in 2 steps
