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11 Cards in this Set
- Front
- Back
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What is the most abundant protein in the human body, its main function, and about how much is in a typical person?
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Collagen, maintain shape and resist deformation of tissues.
150lb person has about 13lb of collagen. |
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What are the general amino acid composition characteristics of collagen? What are precollagen, procollagen, tropocollagen?
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33% glycine, 10% proline and hydroxyproline, and 1% hydroxylysine. Composed of Left turning alpha helixes. Interchain H bonding stabilizes structure into 3 alpha helixes.
Pre = initial form of collagen whose signal peptides will be cleaved off by peptidase. Pro = result of peptide cleavage. Extra amino acids in N and C terminus required for stability and assembly. Tropo = when extra terminal amino acids are removed prior to secretion. |
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Describe 4 modifications that take place to procollagen? Which one requires vitamin C?
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Hydroxylation = requires vitamin D
Glycosylation = attachment of sugar N-Linked glycosylation Disulfide bond formation |
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What is elastin, its color, and what is its function?
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Yellow insoluble protein. Major component of elastic tissue like blood vessels.
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What are the similarity and differences between the amino acid compositions of collagen and elastin?
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Elastin is also 1/3 glycine but has much more valine and alanine
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What enzyme modifies lysines to a form, which will eventually cause cross linking to occur in collagen and in elastin? What are the structures in elastin crosslinks called?
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Lysyl Oxidase
Desmosine. |
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What general composition characteristic of proteoglycans makes them dramatically different from collagen or elastin?
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Form ground substance of extracellular matrix. 95% polysaccharide.
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What 3 genreal structural characteristics do proteoglycans have in common?
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1) Repeating disaccharide units of D-glucosamine or D-galactosamine.
2) All except keratan sulfate have uronic acid. 3) All except hyaluronic acid have an ester sulfate group |
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Name 4 different proteoglycans, and give their approximate molecular weights?
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1) Hyaluronic acid 4-8 x 10^6
2) Chondroitin .5-5 x 10^4 3) Dermatan sulfate 1.5-4 x 10^4 4) Heparin, heparen sulfate 10^3 -> 10^6 |
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What are the 2 different types of fibronectins, and what functions do they perform?
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Soluble and insoluble.
Play a role in cell adhesion and cell morphology. |
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What are the structural features of fibronectin, and to what does each domain bind?
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2 chains joined at C terminus by disulfide. Each chain has 3 domains.
32kd = binds glycosaminoglycans 40kd = binds collagen 140-150kd = binds cell surface as well as glycosaminoglycans |
