Procollagen peptidase

PROCESSIVITY OF KINESIN ATPase PROCHIRALITY CHIRALITY CHIRALITY PROBES PROCOLLAGEN N-PEPTIDASE PRODUCT... 

Extracellular cleavage of procollagen molecules After their release, the procollagen molecules are cleaved by N- and C-pro-collagen peptidases, which remove the terminal propeptides, releasing triple-helical collagen molecules. 

Within the extracellular space two procollagen peptidases act to cleave a 35-kDa peptide from the C terminus631 and a 20-kDa peptide from the N-terminal end of each of the three chains of the secreted procollagen. The amino acid composition of the peptides removed is quite unlike that of the remaining collagen monomer (also called tropocollagen) which contains one-third glycine and much proline. 

The procollagen molecule is secreted from the cell, and the extension propeptides are excised by two specific procollagen peptidases to form the tropocollagen molecule. The removal of the peptides (Mr = 20,000 and 35,000) allows the tropocollagen molecules to self-assemble to form fibrils. This assembly is regulated to some extent by the cells and by other extracellular components to produce the wide variety of structures found in collagen fibers. 

Muller, A., Krombholz, B., Pott, G., Machnik, G., Vollandt, R., Reinhardt, M., Jorke, D. Collagen peptidase and type III procollagen peptide serum levels in chronic liver diseases. Clin. Chim. Acta 1991 197 59-66... 

The procollagen peptidase is sometimes lacking. In other cases a person synthesizes an abnormal pro-o2 chain that is resistant to cleavage by the peptidase because of deletion of the normal cleavage site. In others collagen is formed in only small amounts or is degraded rapidly. Some individuals lack lysyl hydroxylase and others have a defect in mRNA splicing which causes loss of an exon from the mRNA and synthesis of shortened pro-o2 chains. ... 

EDS VII is a combination of classical and vascular EDS caused mostly by in-frame deletions of 18 or 24 amino acid residues encoding exon-6 of COL1A1 or COL1A2, the downstream splice site for procollagen N-peptidase. Mutations of procollagen N-peptidase (Sect. 8.2.1, Fig. 8.5) also cause this form of EDS. 

Either the pro l chains or the assembled procollagen is secreted from the cell where conversion of procollagen to collagen takes place. In this conversion, the teleopeptides are removed (27) by procollagen peptidase to reduce the size of the 1 chains to 95,000. Procollagen... 

The N-terminal residue of the al and < 2 chains of collagen is pyrrolidone carboxylic acid (231). Action of procollagen peptidase on... 

A group of heritable disorders. Clinical features include hyperelastic skin, hyperextensible joints, easy bruising and poor wound healing. Collagen has decreased content of hydroxylysine. Deficient enzyme may be Lysyl oxidase (EC 1.4.3.6), Lysyl protocollagen hydroxylase (EC 1.14.11.4) or Procollagen peptidase (C-endopeptidase EC 3.4.24.19, or A-endopepti-dase EC 3.4.24.14). 

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