32. Biochemistry: Extracellular Matrix Proteins Questions Study Guide Graded A+

d. all of the above are characteristics of MMP {Ans: MMP have all of the following characteristics EXCEPT: a. contain a Zn in the catalytic domain b. secreted as inactive precursors c. The active MMPs are inactivated by tissue inhibitors of MMP (TIMPs) d. all of the above are characteristics of MMP}e. defects from vitamin C are irreversible {Ans: The modification of the proline residues in collagen biosynthesis increases the stability of the collagen triple helix. These hydroxylations require the enzymes prolyl hydroxylase or lysyl hydroxylase and the cofactor ascorbic acid (Vitamin C). What is FALSE regarding the result of a diet lacking of vitamin C? a. collagen has a lower content of hydroxyproline and hydroxylysine b. scurvy c. collagen has a lower melting temperature than usual d. collagen become more fragile e. defects from vitamin C are irreversible}3, 4, 2, 1, aaaaaand 5 {Ans: Put the steps of collagen biosynthesis in order: 1. Disulfide bond formation at C-terminus align the three alpha chains before the triple helix forms. 2. Glycosylation: Some of the hydroxylysines and asparagine residues at the C-terminus are glycosylated (galactose/glucose added) 3. Polypeptide chain begins to synthesize 4. Hydroxylation: Several prolines (and some