3 nots - 1 Lecture 3 Italized sentences are taken verbatim...

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1 Lecture 3 September 15, 2008 Italized sentences are taken verbatim from Alberts or the web Extracellular processing of fibrillar collagens A key event that occurs in extracellular compartments is the removal of the globular N- and C-terminal propeptides by procollagen N- and C-terminal proteinases. Remove of the C-propeptide leads to a decrease in the critical concentration required for fibril assembly. Hence, removal of the C-propeptide triggers self-assembly into fibrils. Enzymes with collagen 1 C-proteinase activity belong to the tolloid family of Zn- dependent metalloproteinases: bone morphogenetic protein 1 (BMP1), mammalian tolloid (mTLD) and tolloid-like 1(TLL1). Enzymes with collagen 1 N-proteinase activity belong to the ADAMTS ( a disintegrin and metalloproteinase with thrombospondin motif) family: ADAMTS-2, -3, and -14. Diseases associated with improper ER processing Scurvy: a description of the molecular basis of scurvy is presented on page 1099 of Alberts, 4 th Ed. Some of the slides presented in class contain further information. Pathophysiology: http://en.wikipedia.org/wiki/Antiscorbutic Normal collagen synthesis depends upon the hydroxylation of proline and lysine residues in the endoplasmic reticulum, to form hydroxyproline and hydroxylysine , respectively. Prolyl and lysyl hydroxylase , the enzymes that catalyze the hydroxylation reactions, require vitamin C as a cofactor. In cases of chronic deficiency, hydroxyproline and hydroxylysine are not formed in appreciable amounts and the resulting collagen fibrils are considerably weaker. This is due in part to the loss of hydrogen bonding between hydroxyprolines and constituent heteroatoms within the collagen α -helical trimer, which otherwise confer mechanical stability. Scurvy phoenity.com/diseases/scurvy.html Alternative names: vitamin C deficiency; deficiency - vitamin C; scorbutus A condition characterized by general weakness, anemia, gumdisease (gingivitis), and skin hemorrhages resulting from a lack of ascorbic acid (Vitamin C) in the diet. Scurvy is now most frequently seen in older, malnourished adults. Scurvy was a serious problem in the past, when fresh fruitstand vegetables were not
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  • Fall '08
  • ringuitte
  • Collagen, Scurvy, collagen fibrils, http://en.wikipedia.org/wiki/Antiscorbutic Normal collagen, collagen α-helical trimer, pro alpha chains

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3 nots - 1 Lecture 3 Italized sentences are taken verbatim...

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