Question

1. Frequently when an enzyme or protein is heated above about 60C it loses its biological activity. Describe in molecular terms what is happening to the protein.

2. Which amino acids form disulfide bonds? What role do these bonds play in determining protein conformation?

3. What type of bonds are important in stabilizing an α helix? Explain.

4. Where are the R-groups found in an α helix? Why?

5. Glycine is found as every third amino acid in the helical regions of type I collagen. Why? Is glycine a major component of α helices?

6. Kinetically, how do allosteric enzymes differ from enzymes that display Michaelis-Menten kinetics?

7. When [S] is less than Km, v is first order with respect to [S]. What does this mean?

8. Below is the titration curve for Asp. The pKa values are 2.0 (COOH), 3.9 (side chain), 9.9 (NH ).
Identify the isoelectric point.
The point at which the pH = pKa of the amino group.
The pH ranges where buffering is best. Why?

Answer 1

1- the term use for the enzyme which loses biological activity after 60 degree centigrade temperature is denaturation of protein.

2- there are 2 amino acid out of 20 are responsible for disulfide Bond formation these are cysteine and methionin. This type of Bond are responsible for the tertiary and quaternary structure of protein.

3- Alpha helical structure the hydrogen bond are responsible for the stability of this is structure and protein.

4- in Alpha helical structure the group is situated as. the R groups of the amino acid residues protrude outward from the helical backbone. Attitude it outside increase the surface area for hydrogen bonding and make more stable configuration.

5- in collagen Type 1 glycine amino acid is the major contributor of amino acid that is every third amino acid is glycine because glycine is smallest amino acid and provide flexibility in Alpha helical structure in few Type 1 collagen protein.

Blessing is not a major component of all the Alpha helical protein but it is the major component of Type 1 collagen protein.