Quiz 5 (Ocular GAGs, Lipid Storage Disorders, Eicosanoids, Graves' disease, Steroids, & Other Hormones)

What are the two sides of the connective, extracellular tissue found in the eye?

Collagen and GAG

T/F: Hyaluronate absorbs a lot of water

True

What is a glycoprotein?

A protein to which sugars are bound

What are some notable features of a GAG?

-N-acetylated group in the right hand sugar

-Negative charges on the carboxylate and sulfate groups

-Alternating β 1-3 and β 1-4 linkages

-Sulfation might take place in several positions

A carboxylate in the up position is what?

Uronate

A carboxylate in the down position is what?

Iduronate

Where is hyaluronic acid found?

Vitreous

Where is keratan sulfate found?

Cornea

Where is dermatan sulfate found?

Cornea

Do corneal GAGs (keratan sulfate and dermatan sulfate) have longer or shorter lengths than the vitreous GAG (hyaluronic acid)?

Shorter

What does a glycoprotein have bound to it?

Oligosaccharides

What does a proteoglycan have bound to it?

GAGs

In this class, does "proteoglycan" refer to the holoprotein or the apoprotein?

Holoprotein

What is an example of a glycoprotein?

Rhodopsin

What is an example of a proteoglycan?

Lumican

What is the link of an oligosaccharide?

Gal-Gal-Xylose-Ser-Protein

What are the two corneal proteoglycans?

Decorin and lumican

Lumican binds to...

Only keratin sulfate

Decorin binds to...

Chondroitin sulfate, dermatan sulfate, or keratan sulfate

T/F: The corneal proteoglycans exhibit some viscoelasticity?

True

What is the name of the disease that occurs when GAGs are not moved to lysozymes?

Mucopolysaccharidoses

What is MPS IH?

Hurler's syndrome

Is there corneal opacification with Hurler's syndrome?

Yes

Is there retinal pigmentary degeneration with Hurler's syndrome?

Yes

Is there optic atrophy with Hurler's syndrome?

Yes

Is there mental retardation with Hurler's syndrome?

Yes

Is there cardiovascular issues with Hurler's syndrome?

Yes

Is there skeletal dysplasia with Hurler's syndrome?

Yes

What is the enzymatic defect with Hurler's syndrome?

⍺-ʟ-iduronidase

What is the excessive GAG in Hurler's syndrome?

Dermatan sulfate and heparan sulfate

What is the inheritance of Hurler's syndrome?

Recessive

What are the treatments for Hurler's syndrome?

-bone marrow/umbilical cord blood transplantation

-enzyme replacement therapy

-gene replacement therapy

What is the "red spot" in storage diseases involving lipids consistent with?

Tay-Sachs disease

What causes Tay-Sachs disease?

Hexosaminidase A deficiency

What populations are more likely to get Tay-Sachs disease?

Ashkenazi Jews, Cajuns, and French Canadians

What does Inclusion-Cell Disease resemble?

Hurler's syndrome

What causes Inclusion-Cell disease?

A defect in a packaging enzyme that prepares β-galactosidase for transport to its lysozyme

What enzyme is defective in I-Cell Disease?

N-acetylglucosamine-1-phosphotransferase