Activity and Extractability of Lysyl Oxidase and Collagen Proteins in Developing Granuloma Tissue 1 2

Summary

The total activity of lysyl oxi-dase and its extractability into phosphate and 4 M and 8 M urea solutions were studied in granuloma tissue formed around sub-cutaneously implanted polyvinylalcohol sponges in rats and harvested on days 10, 18, 26, and 34. Furthermore, total collagen content and fractions of collagen extractable into 0.45 M NaCl (NSC) and 0.5 M acetic acid (ASC) were studied. Lysyl oxidase activity was assayed by measuring the release of tritium from a substrate biosynthetically labeled with H³-6-Lysine. Biochemical data were compared to the histology of the tissue.

With the maturation of the granuloma tissue, the total activity of lysyl oxidase significantly decreases, and its extractability into phosphate significantly increases. Extractability into 4M urea was the highest in 10-day-old granuloma and the lowest in 34-day-old tissue. Only 80% of the total activity was extracted into 4 M urea medium. Total collagen content and ASC fraction increased continuously, and NSC decreased from 2.5% to 1.2% in 34-day-old tissue.

We conclude that the highest activity of lysyl oxidase in young granuloma is related to a high proportion of fibroblasts and that the enzyme at this time is tightly bound to the pellet, possibly to the collagen substrate.