BIO ALGEBRA OF LIVING ORGANISMS

(Bio Mathematical Lab of Sikander Aqeel) 

CHAPTER 3 PROTEINS  

Proteins  

(2/26/2016) 

Amino Acid Sequence of Polypeptide Chain: 

The next step is to identify the amino-terminal and the carboxyl-terminal residues of the polypeptide chain, the first successful method, developed by F. Sanger utilized the reaction between the free a-amino group of the amino-terminal residue of the chain with 2.4 dinitrofluorobenzene to form a yellow 2,4 dinitrophenyl (DNP) derivative, when such a DNP derivative of a polypeptide is subjected to hydrolysis with 6 N HCl, all the peptide bonds are hydrolyzed, however the bond between 2,4 dinitrophenyl group, 

Tetrapeptide = C18H10N4O5 = 216 + 12.5 + 56 + 80 = 364.5 mole 

Hydrogen chloride = HCl = 36.25 mole

For example 

  = a2 + b2 = c2 

  = a2 = CHl and b2 = 24 hours = c2 

  = a2 = 1.25 (H) + 35 (Cl) and b2 =  24 = c2 

  = a2 = 36.25 + b2 = 24 = c2 

  = a36.25 + b24 = c2 

  = 1314.0625 + 576 = c2 

  = a + b = 1890.0625 = c2 

  = a + b = 1890.0625 / 43.5 = 43.5

 = 43.5 * 8.37931 FDNB = 364.499985, (FDNB C5H10N2O4 = 164.5 / 18.5 water = 8.8918) 

(FDNB) 364.5 mole = Tetrapeptide = HF  

(FDNB) 364.5 mole – 1.25 = 363.25 (2,4 dinitrophenyl Tetrapeptide) 

(FDNB) 363.25 mole --- 3H2O = 55.5 + 30.25 P -------- 85.75 m/g = C3H3NO2 = (2.4 dinitrophenyl-amino acid corresponding to the NH2 terminal residue) 

2.4 dinitrophenyl-amino acid corresponding = 85.75 + 333 mole = 418.75 mole free amino acids, 

Free amino acids = C15H12N3O6 = 180 + 15 + 42 + 96 = 333 

Free amino acids = 333 mole 

2.4 dinitrophenyl = 85.75  

                 Total = 418.75 mole free amino acids  

Total answer is 

FDNB—HF— Tetrapeptide----> FDNB 2,4 dinitrophenyl Tetrapeptide-------> NH2—terminal corresponding 

And it occurs from 8.89 mole water of FDNP system, which make able to amino acid corresponding for free amino acids, and this long polypeptide chain, can be “sequenced” automatically by the Sikande Aqeel method, because when such a DNP derivative of a polypeptide is subjected to hydrolysis with 6 N HCl, all the peptide bonds are hydrolyzed, however the bond between 2,4 dinitrophenyl group,