Format

Send to:

Choose Destination
See comment in PubMed Commons below
J Clin Invest. 1989 Oct;84(4):1076-85.

Lipocytes from normal rat liver release a neutral metalloproteinase that degrades basement membrane (type IV) collagen.

Author information

  • 1Liver Core Center, San Francisco General Hospital, California 94110.

Abstract

We report a proteinase that degrades basement-membrane (type IV) collagen and is produced by the liver. Its cellular source is lipocytes (fat-storing or Ito cells). Lipocytes were isolated from normal rat liver and established in primary culture. The cells synthesize and secrete a neutral proteinase, which by gelatin-substrate gel electrophoresis and gel filtration chromatography, has a molecular mass of 65,000 D. The enzyme is secreted in latent form and is activated by p-aminophenylmercuric acetate but not by trypsin. Enzyme activity in the presence of EDTA is restored selectively by zinc and is unaffected by serine-protease inhibitors. In assays with radiolabeled soluble substrates, it degrades native type IV (basement membrane) collagen but not interstitial collagen types I or V and exhibits no activity against laminin or casein. At temperatures causing partial denaturation of soluble collagen in vitro, it rapidly degrades types I and V. Thus, it is both a type IV collagenase and gelatinase. The enzyme may play a role in initiating breakdown of the subendothelial matrix in the Disse space as well as augmenting the effects of collagenases that attack native interstitial collagen.

PMID:
2551922
[PubMed - indexed for MEDLINE]
PMCID:
PMC329763
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Journal of Clinical Investigation Icon for PubMed Central
    Loading ...
    Write to the Help Desk