Abstract
Some enzymes requiring coenzymes derived from vitamins are involved in the amino acid metabolism of various organisms. For example, some pyridoxal 5’-phosphate (PLP)-dependent enzymes and flavin adenine dinucleotide (FAD)-dependent L-amino acid oxidases participate in several metabolic pathways including the biosynthesis and degradation of amino acids. :e constructed the recombinant expression system and large-scale purification procedure of some useful coenzyme-dependent enzymes, such as L-glutamate oxidase (LGOX), L-lysine Į-oxidase (LysOX), L-methionine Ȗ-lyase (MGL), and isocitrate dehydrogenase (ICDH), and determined the X-ray crystallographic structures of these enzymes, and elucidated the mechanisms by which they recognize their substrates and cofactors. :e determined the special characteristics and three-dimensional structure of these unique enzymes and conducted the functional analysis of these enzymes based on their structures and thereby studied the structure-function correlation of these enzymes. In addition, we attempted the application of these enzymes to medical and analytical researches (e.g., biosensor and analytical enzyme or diagnostic enzyme). Among them, LysOX and MGL inhibited the growth of a wide variety of cancer cells but showed a low toxicity for normal cells. LysOX , MGL and L-methionine decarboxylase (MetDC) are potentially useful for cancer therapy.
