The sequence of amino acids of the protein trypsin Inhibitor

The sequence of amino acids of the protein trypsin Inhibitor is known. Following is a list of amino acids and the number of each in the trypsin inhibitor molecule. Based on this table and the structures of the amino acids (Figure 5.14 in your textbook), how many negatively charged amino acids are present in this molecule? Based on this table and the structures of the amino acids, how many positively charged amino acids are present in this molecule? Based on this table and the structures of the amino acids, how many polar (but not charged) amino acids are present in this molecule? What is the maximum number disulfide bonds this protein can have? This protein has 179 amino acids. Based on the amino acid composition, this protein is predominantly neutral negatively charged positively charged

Solution

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Based on this table and the structures of the amino acids (Figure 5.14 in your textbook), how many negatively charged amino acids are present in this molecule?

Aspartic acid =12

Glutamic acid = 9

Total = 21 negatively charged amino acids

Based on this table and the structures of the amino acids, how many positively charged amino acids are present in this molecule?

Lysine=8

Arginine= 14

Histidine=5

Total = 27 positively charged amino acids

What is the maximum number disulfide bonds this protein can have?

Two cysteine amino acids together make one disulfide bond

So 4 cysteines make total of 2 disulfide bonds

This protein has 179 amino acids. Based on the amino acid composition, this protein is      

Since there are more positively charged amino acids, this protein is

c.positively charged