Modulation of lysyl oxidase by dietary copper in rats

Robert B. Rücker, Nadia Romero-Chapman, Toniel Wong, Jill Lee, Francene M. Steinberg, Carl Mcgee, Michael S. Clegg, Karen Reiser, Taru Kosonen, Janet Y. Uriu-Hare, Jerome Murphy, Carl L Keen

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Abstract

Lysyl oxidase levels were estimated in rat tissues using an enzyme-linked immunosorption assay (ELISA) and a functional assay standardized against known amounts of purified lysyl oxidase. High concentrations of lysyl oxidase (≥150 μg/g of tissue or packed cells) were detected in connective tissues, such as tendon and skin. Values for aorta, kidney, lung and liver ranged from 30 to 150 μg/g of tissue; values for skeletal muscle and diaphragm were <30 μg/g tissue. Purified rat skin lysyl oxidase catalyzed the release of 50- 100 Bq of tritium per μg enzyme in assays that used 3H-elastin-rich substrates. In dense connective tissues, good agreement was obtained for the values from ELISA and those derived from measurements of functional activity in aorta, lung, skin and tendon (r2 > 0.9). When egg white-based experimental diets containing 2 or 10 μg/g added copper were fed to weanling rats, values for skin lysyl oxidase functional activity in the group fed 2 μg/g added copper were one-third to one-half the values for skin lysyl oxidase functional activity in rats fed 10 μg/g copper. This reduction in lysyl oxidase activity, however, had minimal effect on indices of collagen maturation in rat skin, e.g., collagen solubility in neutral salt and dilute acid or the levels of acid stable cross-links. Moreover, copper deficiency did not influence the steady-state levels of lysyl oxidase specific mRNA in rat skin or the apparent amounts of lysyl oxidase in rat skin as determined by ELISA. These observations underscore that the concentration of lysyl oxidase is relatively high in dense corrective tissues, and although decreasing dietary copper influences functional activity, there is little apparent effect on the production of lysyl oxidase protein.

Original languageEnglish (US)
Pages (from-to)51-60
Number of pages10
JournalJournal of Nutrition
Volume126
Issue number1
StatePublished - Jan 1996

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Keywords

  • collagen
  • copper
  • elastin
  • lysyl oxidase
  • rats

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Food Science

Cite this

Rücker, R. B., Romero-Chapman, N., Wong, T., Lee, J., Steinberg, F. M., Mcgee, C., Clegg, M. S., Reiser, K., Kosonen, T., Uriu-Hare, J. Y., Murphy, J., & Keen, C. L. (1996). Modulation of lysyl oxidase by dietary copper in rats. Journal of Nutrition, 126(1), 51-60.