Denaturation of Proteins

What is the difference between denaturation and coagulation?

-denarutration: loss of 3D shape = loss of function -coagulation: when protein molecules clump together, proteins do not need to be denatured in order to coagulate

As you increase the temperature of an enzyme-catalyzed reaction, the rate of reaction initially increases. It then reaches a maximum rate and finally dramatically declines. Keeping in mind that enzymes are proteins, how do you explain these changes in reaction rate?

the additional heat energy will eventually begin to interfere with the weak interaction that maintain the essential 3-dimensional structure of the enzyme, ultimately denaturing the protein When the conformation of the enzyme active site loses its characteristic 3-dimensional shape or its characteristic charge distribution, the enzyme is no longer functional

Why do proteins become polycations at extremely low pH?

the carboxyl groups become protnated

Define the term denaturation

the loss of the structural order of a protein (secondary, tertiary, quarternary-or a combination of these) -resulting in a completely disorganized, nonfunctional form of the protein

Denaturation can be brought about by:

-heat -large changes in pH (alters charge onside chains) -detergents such as SDS (disrupts hydrophobic interactions) -urea and guanidine (disrupts H bonding) -mercaptoethanol (reduces disulfide bonds)

Why is it important that blood have several buffering mechanisms to avoid radical pH changes?

Extreme pH change is one way that the charges in the side chains of proteins can be altered and the protein can be denatured to avoid this it is important that blood is able to keep a balanced pH

Why is heat an effective means of sterilization?

because it destroys (through denaturation) the proteins of microbial life-forms, including fungi, bacteria, and viruses

Define the term isolectric

having a net charge of zero (the charges in the peptide chain add up to zero)