3-Methylaspartate ammonia-lyase from a facultative anaerobe, strain YG-1002.
3-Methylaspartase was purified 24-fold and crystallized from the crude extract of the cells of a facultative anaerobic bacterium from soil, strain YG-1002. The molecular mass of the native enzyme was about 84 kDa and that of the subunit was about 42 kDa. The pH optimum for the deamination reaction of (2S, 3S)-3-methylaspartic acid and those for the amination reaction of mesaconic acid were 9.7 and 8.5; its optimum temperature was 50 degrees C. The enzyme was stable at pH 5.5-11.0 and up to 50 degrees C. The enzyme required both divalent and monovalent cations such as Mg2+ and K+. The enzyme was inhibited by sulfhydryl reagents, metal-chelating reagents and some divalent cations. The enzyme catalyzed the reversible amination/deamination reactions between several 3-substituted (S)-aspartic acids and their corresponding fumaric acid derivatives. The enzyme preferentially acted on (2S, 3S)-3-methylaspartic acid and mesaconic acid in the deamination and the amination reactions respectively. The enzyme showed high similarities in several enzymological properties and N-terminal amino acid sequence with 3-methylaspartase from an obligate anaerobic bacterium Clostridium tetanomorphum.
Kato
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Biotechnology Research Center, Faculty of Engineering, Toyama Prefectural University, Japan.
Asano
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Y
D000595:Amino Acid Sequence; D000642:Ammonia-Lyases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D001421:Bacteria, Anaerobic / Q000201:enzymology*; D002413:Cations, Divalent / Q000494:pharmacology; D002414:Cations, Monovalent; D002614:Chelating Agents / Q000494:pharmacology; D003460:Crystallization; D004791:Enzyme Inhibitors; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D017421:Sequence Analysis; D013379:Substrate Specificity; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D013696:Temperature
D002413:Cations, Divalent; D002414:Cations, Monovalent; D002614:Chelating Agents; D004791:Enzyme Inhibitors; D013439:Sulfhydryl Reagents; D000642:Ammonia-Lyases; C034881:methylaspartate ammonia-lyase