Enzyme Commission Designation

Lysyl oxidase is an amine oxidase with the numerical designation of EC

and extracellular forms of the enzyme exist. Although the mechanism(s) of action remains unclear, there is loss of expression of lysyl oxidase in malignant cells (6). It is speculated that the intracellular form(s) of lysyl oxidase targets oncogenic and growth-promoting transcription factors as substrates. Two examples are the RAS oncogene and IRF-1 transcription factor (79). Moreover, lysyl oxidase is also found in the cell nucleus (10).

Within the extracellular matrix (ECM), lysyl oxidase catalyzes the crosslinking of the collagens and elastin. Developmental processes beyond gastrulation are blocked when lysyl oxidase is inhibited (11-13).

For the food chemist, a general knowledge of lysyl oxidase function is essential. In general, the location and types of cross links in collagen and elastin have profound influence on their tensile and elastic properties. For example, an increase in the amount, or a change in the distribution, of crosslinked collagen in edible meats affects rheological properties (4, 14). In addition, crosslinking renders collagen and elastin less susceptible to proteolysis (15). Therefore, a decrease in lysyl oxidase activity is often associated with increased proteolysis of collagens and elastin, or altered tensile and elastic properties.

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