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Biotin condensed through its carboxyl group with the ε-amino group of a lysyl residue in the apoenzymes to which biotin is the coenzyme; the predominant linkage in which biotin is found.
biocytinBiotin covalently linked to lysine. Biocytin is an intermediate in biotin metabolism, and is found in serum and excreted in urine.
A complex molecule of biotin and lysine released from digested protein to act as a catalyst in the tricarboxylic acid cycle.