Treponema denticola cystalysin catalyzes β‐desulfination of L‐cysteine sulfinic acid and β‐decarboxylation of L‐aspartate and oxalacetate

FEBS Letters

Bertoldi, Mariarita¹  Borri Voltattorni, Carla¹  Cellini, Barbara¹ 

[1] Dipartimento di Scienze Neurologiche e della Visione, Sezione di Chimica Biologica, Facoltà di Medicina e Chirurgia, Università degli Studi di Verona, Strada Le Grazie, 8, 37134 Verona, Italy

关键词: Cystalysin;    Pyridoxal 5′-phosphate;    β-Decarboxylation;    β-Desulfination;    PLP;    pyridoxal 5′-phosphate;    PMP;    pyridoxamine 5′-phosphate;   

DOI  :  10.1016/S0014-5793(03)01178-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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.

【 授权许可】

Unknown