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Treponema denticola cystalysin catalyzes β‐desulfination of L ‐cysteine sulfinic acid and β‐decarboxylation of L ‐aspartate and oxalacetate
Author(s) -
Cellini Barbara,
Bertoldi Mariarita,
Borri Voltattorni Carla
Publication year - 2003
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(03)01178-5
Subject(s) - chemistry , decarboxylation , treponema denticola , cysteine , stereochemistry , biochemistry , enzyme , bacteria , catalysis , biology , porphyromonas gingivalis , genetics
Pyridoxal 5′‐phosphate‐dependent cystalysin from Treponema denticola catalyzes the β‐displacement of the β‐substituent from both L ‐aspartate and L ‐cysteine sulfinic acid. The steady‐state kinetic parameters for β‐desulfination of L ‐cysteine sulfinic acid, k cat and K m , are 89±7 s −1 and 49±9 mM, respectively, whereas those for β‐decarboxylation of L ‐aspartate are 0.8±0.1 s −1 and 280±70 mM. Moreover, cystalysin in the pyridoxamine 5′‐phosphate form has also been found to catalyze β‐decarboxylation of oxalacetate as shown by consumption of oxalacetate and a concomitant production of pyruvate. The k cat and K m of this reaction are 0.15±0.01 s −1 and 13±2 mM, respectively. Possible mechanistic and physiological implications are discussed.