Biochemistry Fibrous Proteins

Front 1

where do you find collagen dispersed as a gel

Back 1

in the vitreous humor of the eye

Front 2

a typical collagen molecule consists of a triple-stranded helix composed of 3 ___________

Back 2

alpha-chains, each one about 1000 amino acids long

Front 3

collagen is (soluble/insoluble)

Back 3

collagen is insoluble

thats why it has to be formed as soluble precollagen inside the cell, so it can get out

Front 4

3 cell types that can produce collagen

Back 4

fibroblasts

chondroblasts

osteoblasts

Front 5

the 3 main amino acids of collagen

Back 5

glycine, proline and lysine

Front 6

collagen has which amino acid every third position

Back 6

glycine, they're super small

Front 7

which amino acid of collagen forms the kinks that facilitate winding of the alpha chains

Back 7

proline, its awkward and kinky

Front 8

the alpha chains that will be collagen are extruded into the endoplasmic reticulum where proline and lysine residues are selectively hydroxylated

at this stage where and why are disulfide bonds formed

Back 8

in the procollagen molecule disulfide bonds are formed at the N and C terminal ends to lock up the structure like a tight rope

Front 9

how many genes code for collagen

Back 9

2

pro-alpha-1
pro-alpha-2

the combination of the protein chains generates the different types of collagen

Front 10

selected proline and lysine residues of the alpha-collagen chains are hydroxylated

what will you call the enzymes that do this

Back 10

prolyl hydroxylase

lysyl hydroxylase

of course, they require molecular oxygen and vitamin C

Front 11

of what use are hydroxyproline residues to collagen

Back 11

hydroxyproline residues stabilize the chain structure by maximizing interchain H-bonding between the 3 alpha chains

Front 12

of what use are hydroxylysine residues to collagen

Back 12

hydroxylysine residues may be glycosylated

more importantly, they are involved in crosslinking BETWEEN collagen MOLECULES in the ECM, resulting in tensile strength

Front 13

in collagen, hydroxylysine covalently links with allysine

what is allysine?

Back 13

allysine is a lysine residue that has been deaminated, it has an aldehyde group out there instead, which is where the name comes from

enzyme: lysyl oxidase

Front 14

what do you call the syndrome resulting from a mutation in the pro-alpha chains

Back 14

Ehelers-Danlos Syndromes

over 20 different genetic defects related to hypermobility of joints, hyperextensibility of the skin, fragility of the skin

problems with enzymes like
prolyl hydroxylase
lysyl hydroxylase
lysyl oxidase
etc

Front 15

where is procollagen cleaved to collagen

Back 15

in the ECM

becomes insoluble in the process

Front 16

what 3 disorders may be associated with a blue sclera

Back 16

osteogenesis imperfecta

Ehlers-Danlos Syndrome

Marfan's Syndrome

Front 17

there's 8 types of Osteogenesis Imperfecta

which number is the worst, which one is the mildest

Back 17

Osteogenesis Imperfecta

1 is the mildest

2 is the most severe

4 is the most common

Front 18

Osteogenesis Imperfecta Type I

Back 18

Type I Osteogenesis Imperfecta Tarda

long bone fractures, often early in infancy, becoming less likely in adulthood

blue sclera

normal height, predisposition to hearing loss

Front 19

Osteogenesis Imperfecta Type II

Back 19

Type II Osteogenesis Imperfecta Congenita

death in utero due to respiratory problems

Front 20

does lysyl oxidase convert those lysine residues to allysine intra- or extra- cellularly

Back 20

extracellularly

Front 21

the cross links of elastin

Back 21

desmosine

Front 22

tropoelastin is secreted into the extracellular space where it interacts with-

Back 22

fibrillin, the elastic fiber scaffold

Front 23

one third of amino residues in elastic fibers are ________

Back 23

glycine

little, little glycine

Front 24

elastic fibers have none of these modified residues

Back 24

elastic fibers have

NO HYDROXYPROLINE or HYDROXYLYSINE because its elastic, you want some areas to repel each other

rich in proline and lysine, though

Front 25

how do elastin chains link to the Desmosine crossbridge

Back 25

elastin chains use

3 allysine residues and 1 lysine residue to link FOUR elastin chains

makes elastin yellow

Front 26

what can a deficiency of lysyl oxidase result in

Back 26

Aneurisms

Front 27

what is the cofactor for lysyl oxidase

Back 27

copper