Complex sentence: These enzymes are not to be confused with the deiodinase iodotyrosine deiodinase that is a deiodinase but not a member of this family, and (unlike the iodothyronine deiodinases) does not use selenocysteine or selenium.
Split into simpler sentences: These enzymes are not to be confused with the iodotyrosine deiodinases that are also deiodinases, but not members of the iodothyronine family. The iodotyrosine deiodinases (unlike the iodothyronine deiodinases) do not use selenocysteine or selenium.