Module 6: Amino Acids and Proteins Obj. 3

Question 1

Isoelectric point (pI)

Answer 1

pH at which the protein carries net zero charge

Question 2

properties a protein displays at isoelectric point

Answer 2

protein is least stable and least soluble (subject to precipitation)

Question 3

denaturation

Answer 3

caused by breakage of bonds in protein molecule resulting in distribution of tertiary and secondary structure
Changes in chemical, physical, functional properties of the protein
Sometimes proteins can be renatured

Question 4

coagulation

Answer 4

disruption of primary structure (breaking peptide bonds)

Irreversible

Question 5

average pI of plasma proteins

Answer 5

pH 5
Thus proteins are kept in solution because their pI is a long way from normal pH 7.4 at which they have a negative charge