Biochemistry: Glycosaminoglycans, Proteoglycans And Extracellular Matrix

Front 1

Long, unbranched polysaccharides made up primarily of repeating disaccharide units

Back 1

Glycosaminoglycans (GAGs)

Front 2

Proteins with variable amounts of GAG attached:

Back 2

Proteoglycans

Front 3

What are typically the two saccharide units of GAGs made up of?

Back 3

1) N-acetylglucosamine or N-acetylgalactosamine
2) Uronic Acid (Sugar Acid)

Front 4

GAGs are highly _______ charged. Why?

Back 4

Negatively, due to sulfate and carboxylic acid functional groups

Front 5

What is the relationship between GAGs and water? Why?

Back 5

They tend to absorb large amounts of water due to their high negative charge.

Front 6

A group of disorders resulting from defects in degradation of GAGs

Back 6

Mucopolysacchridoses

Front 7

Undegraded or partially degraded GAGs accumulate where?

Back 7

In the lysosomes: are lysosomal storage diseases

Front 8

What are the two main classes of molecules that make up the extracellular matrix?

Back 8

GAGs/proteoglycans and fibrous proteins

Front 9

Name two tissue types that impart structural properties to the extracellular matrix:

Back 9

Collagen and Elastin

Front 10

Name two tissue types that give the extracellular matrix its adhesive properties

Back 10

Fibronectin and laminin

Front 11

What is the major structural protein of the ECM?

Back 11

Collagen

Front 12

What it the amino acid repeat in collagen?

Back 12

Gly-X-Y
X is often Pro, Y is often hydroxyproline

Front 13

Describe the helical structure of collagen:

Back 13

Collagen chains are left handed helices that combine to form a right handed triple helix.

Front 14

Collagen is synthesized as a precursor that contains a small amino-terminal targeting signal that does what?

Back 14

Directs the growing chain to the ER.

Front 15

________ residues stabilize the collagen triple helix by interchain hydrogen bonds.

Back 15

Hydroxyproline

Front 16

_________ is important for glycosylation of collagen and for the formation of covalent crosslinks.

Back 16

Hydroxylysine

Front 17

Sequences found at the amino and carboxy termini that are necessary for triple helix formation but do not become part of the triple helix.

Back 17

The propieces of procollagen

Front 18

What are the two roles of propieces of procollagen?

Back 18

1. assist in the formation of triple helix
2. preventing collagen molecules from aggregating within cells

Front 19

Collagen is stabilized by ______ crosslinks.

Back 19

Covalent

Front 20

Lysyl oxidase plays what role in collagen formation? What does it require?

Back 20

It helps to form the covalent crosslinks and requires copper containing enzyme.

Front 21

How is type IV collagen distinct from other collagen types?

Back 21

It is restricted to basal lamina.

Front 22

Collagen degradation is initiated by what enzyme? How does it work?

Back 22

Collagenase, it cleaves the collagen triple helix into two fragments that denature at physiologic pH.