Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Amino acid mature elastin

Elastin is a macromolecule synthesized as a 70,000 single peptide chain, termed tropoelastin and secreted into the extracellular matrix where it is rapidly crosslinked to form mature elastin. The carboxy-terminal end of elastin is highly conserved with the sequence Gly-Gly-Ala-Cys-Leu-Gly-Leu-Ala-Cys-Gly-Arg-Lys-Arg-Lys. The two Cys residues that form disulfide crosslinks are found in this region as well as a positively charged pocket of residues that is believed to be the site of interaction with microfibrillar protein residues. Hydrophobic alanine-rich sequences are known to form a helices in elastin these sequences are found near lysine residues that form crosslinks between two or more chains. Alanine residues not adjacent to lysine residues found near proline and other bulky hydrophobic amino acids inhibit a helix formation. Additional evidence exists for (3 structures and 3 turns within elastin thereby giving an overall model of the molecule that contains helical stiff segments connected by flexible segments. [Pg.56]

AMINO ACID COMPOSITION (EXPRESSED AS RESIDUES PER 1000 TOTAL RESIDUES) OF TYPICAL MATURE ELASTIN, MATRIX COLLAGEN AND MICROFIBRILLAR PROTEIN PREPARATIONS. [Pg.67]

For purposes of this manuscript, we wish to concentrate only on the steps leading to the formation of desmosines, amino acids found predominantly in elastin. With respect to their formation, the following suggests their spontaneous formation from peptidyl lysine and the oxidation product, peptidyl allysine. Narayanan et al. (28,29) have shown that when purified lysyl oxidase and non-crosslined elastin, specifically tropoelastin, are incubated together, the desmosines are formed. Desmosine formation, however, only occurs at temperatures that favor fibrillar arrangements of tropoelastin. Subsequently, it is felt that the maturation of non-crosslinked elastin into cross-linked elastin appears to involve only two major steps, namely insolublization through the formation of fibrils and fixation of the fibrils by crosslinking. [Pg.73]

Elastin is a major structural protein element found in many connective tissues that is known to impart resiliency and elasticity to mechanically loaded tissues. It is therefore no suiprise that the material has become an important tool in tissue engineering research [98]. Mature elastic fibers found in tissues contain structural subunits called tropoelastin, an amorphous 64 kDa monomer composed of 830 amino acids [14]. In the extiacellular space, the cell-synthesized tropoelastin is exposed to lysyl oxidase-mediated oxidation at available lysine residues and then... [Pg.110]

Mature elastin is a linear polypeptide, tropoelastin, which has a molecular weight of about 72,000 and contains about 850 amino acid residues. Although glycine accounts for one third of the residues, the repeat sequence Gly-X-Y characteristic of collagen is not present in elastin. Instead, glycine residues are present in the repeat units Gly-Gly-Val-Pro, Pro-Gly-Val-Gly-Val, and Pro-Gly-Val-Gly-Val-Ala. Elastin is relatively rich in the nonpolar amino acids alanine, valine, and proline. In contrast to collagen, only a few hydroxyproline residues are present in elastin. Elastin contains no hydroxylysine or sugar residues. [Pg.180]

Elastase is the name given to proteinases that possess the ability to hydrolyze mature cross-linked elastin [18]. Elastin is an insoluble structural protein responsible for the elastic properties of the lung, skin, and arteries and is quite resistant to most proteinases. Elastin is high in hydrophobic amino acid residues such as valine, alanine, glycine, and proline [19]. Insoluble elastin fibers contain cross-links usually between four lysine residues, which form a unique cyclic product, desmosine. The presence of soluble desmosine cross-links in plasma can be used as a measure of elastin breakdown. Of all the elastases in humans, neutrophil elastase has received the most attention over the years due to its broad substrate specificity and abundance within the cell. However, neutrophils and macrophages contain several proteinases (Table 1), which are capable of degrading elastin. [Pg.309]

Table 27.6 Amino acid composition of soluble and mature elastin compared with that of collagen... Table 27.6 Amino acid composition of soluble and mature elastin compared with that of collagen...
Bailey AJ, Ranta MH, Nicholls AC, Partridge SM and Elsden DP (1977) Isolation of a -amino adipic acid from mature dermal collagen and elastin. Evidence for an oxidative pathway in the maturation of collagen and elastin. Biochem Biophys Res Comm 78, 1403-1410. [Pg.91]


See other pages where Amino acid mature elastin is mentioned: [Pg.443]    [Pg.309]    [Pg.5498]    [Pg.243]    [Pg.5497]    [Pg.193]    [Pg.3536]   
See also in sourсe #XX -- [ Pg.67 ]




SEARCH



Elastin

Elastin amino acids

© 2024 chempedia.info