Types of Collagen

Question 1

I

Answer 1

STRONG

• Bone, tendons, skin, most organs, dentin, fascia, cornea
• “one” in bone
• Collagen III –> collagen I in scar formation (collagenase removes collagen III via zinc co-factor)

Question 2

II

Answer 2

Cartilage

-“car-two-lage”

Also in vitreous bodies and nucleus pulposus

Question 3

III

Answer 3

More pliable / easy to stretch

-Granulation tissue, uterus, embryonic tissue, blood vessels

Question 4

IV

Answer 4

Basement membranes, basal lamina, lens

Question 5

Steps of Collagen Synthesis

Answer 5

1- translation of collagen alpha chain (GLY-X-Y usually proline or lysine) AKA preprocollagen

2- Hydroxylate lysine and proline residues (need vit C)

3- Glycosylation of hydroxylysine residues

4- Form triple helix of 3 alpha chains via H+ and disulfide bonds –> procollagen

5- Exocytosis

6- Cleave disulfide rich terminal ends –> insoluble tropocollagen

7- Crosslink into fibrils (lysine - hydroxylysine)