Detection of four isoforms for rat liver Uroporphyrinogen dcarboxylase

RÍOS DE MOLINA M.C.,; CORVI M.M.,; CHAUFAN G.,; GUIDI, S.; SAN MARTÍN DE VIALE L. C.

The Journal of the Argentine Chemical Society. Anales de la Asociación Química .

Asociación Química Argentina

Lugar: Buenos Aires; Año: 1999 vol. 87 p. 121 - 125

Abstract Two isoforms of rat liver Uroporphyrinogen decarboxylase, IfA (MW 45,000) and IfB (MW 30,000), were purified and caracterized. The kinetic values of Km at pH 6.8 –using Uroporphyrinogen III as substrate- was 0.14 mM for IfA, and 0.75 mM for IfB. Using Pentacarboxyporphyrinogen III the values were 1.07 mM for IfA and 1.76 for IfB. Besides, IfA was seven times more efficient than IfB in Uroporphyrinogen decarboxylation, whereas IfB did not show great differences in the catalytic efficiency with bouth substrates. Furthermore, this is the first time that two new isoforms with molecular weights 17,000 and 90,000 were detected.