CT 4 Flashcards
Procollagen molecules are packaged and secreted by passing through the —
Procollagen molecules are packaged and secreted by passing through the Golgi.
Procollagen peptidases cleave the N- and C- terminal of
collagens (Types, I, II, III)
tropocollagen
cleaved product after procollagen
topocollagen
entire (Gly-X-Y]n region and telopeptides
deficiency in procollagen peptidases
Ehlers-Danlos Syndrome Type VII
Hyperextensible skin that bruises easily
Ehlers-Danlos Syndrome Type VII
Ehlers-Danlos Syndrome Type VII
Dislocation of major joints
1/4 stagger for fibril formation with 400 Å gaps between head and tail
tropocollagen
the site of cross-link formation i.e. where insolubilization takes place • nucleation site for calcium deposition in bone
Gaps of fibrils
The structure repeats every — rows.
5
Once the molecules are aligned, they are strengthened by —— cross-linking.
Once the molecules are aligned, they are strengthened by covalent cross-linking.
step 1 ;lysyl oxidases
Oxidation of lysyl (and hydroxylysyl) residues
step 2; Spontaneous condensations
of products of lysyl oxidase reactions form covalent bonds
from step 2; formation of these —– bonds between amino acids located on ——- tropocollagen molecules forms a strong fiber.
formation of these covalent bonds between amino acids located on adjacent tropocollagen molecules forms a strong fiber.
amino termini of lysyl residues are converted to ——-
amino termini of lysyl residues are converted to aldehydes.
need O2 and Cu
lysyl oxidase
aldol cross link
spontaneuous(alfter adehydes are made)
lysinornorluecine crosslink from
aldehyde and NH3+
lysyl oxidase crosslink
are spontaneous
lysyl amino oxidase
can yield one or two aldehydes
2 aldehydes goes thru aldol condensation
to make aldol
link between one aldehyde and Amino group is
lysinonurleucine
(cross link in collagen or elastin)
❂ Hydroxypyridinium
cross-linking of two hydroxylysyl residues and a lysyl residue
Hydroxypyridinium
in collagen
❂ Elastin is synthesized by the cell as a monomer called —-
❂ Elastin is synthesized by the cell as a monomer called tropoelastin
Monomers of tropoelastin are covalently—— to one another renders the elastin fiber highly ——
Monomers of tropoelastin are covalently cross link
to one another renders the elastin fiber highly insol.
tf as tropoelastin is released they are secreted and bind to microfibrils
T
lysyl oxidase).
stimulates Cross-link formation in tropoelastin
The ε amino termini of lysyl residues in elastin are converted to ——
The ε amino termini of lysyl residues in elastin are converted to aldehydes
after aldehyds are made in tropoelastin
aldol crosslinks occur and is a spontaneuous rxn
Desmosine crosslink
3 out of 4 nh2 groups converted to aldehydes
and then desmosine cross link forms
1st step of collagen fibril formation
pro alpha chain made with OH on pro and Lys
glycosylation
addition of N linked oligoscch to hydroxylation residues
occurs after pro alpha chains made and Prolines and Lysine hydroxylated
3 pro alpha chain self assemble thru
disulfide bonds
after self assembly of 3 pro alpha chain
procollagen forms triple helix
and is secreted thru exocytosis
N and C propeptides removed
from procollagen molecule
N and C propeptides removed
prompts formation of collagen fibril
collagen fibrils form
collagen fiber
cov cross link
helps form cov. cross link
formation of collagen fibers
mediated by lysyl oxidase
tropocollagen
allignment into fibrils
gly mutation
trimer disruption (collagen)
tf collagen cant be secreted to cytoplasm
F
can but will be either degraded in cyt or excreted as abnomal fibrils
❂ Collagenases
matrix metalloproteinases (MMPs)
cleave triple helical region of collagens.
collegenase action
Vertebrate collagenases are critical to tissue——- e.g. uterus after pregnancy
Vertebrate collagenases are critical to tissue remodeling e.g. uterus after pregnancy
cleave collagen at >200 sites
Bacterial collagenases
Vertebrate collagenases
approximately 1/4 from the carboxy terminus
