Uroporphyrinogen decarboxylase. Comparative studies between the enzyme coming from rat liver and crab hepatopancreas

CORVI C.,; CHAUFAN G.,; ARMESTO A.,; SAN MARTÍN DE VIALE L. C.,; LUQUET C.,; RÍOS DE MOLINA M. C.

Calgary, Alberta, Canada.

Congreso; Fifth International congress of comparative physiology and Biochemestry; 1999

Comparative Biochemestry and Physiology (CBP)

Uroporphyrinogen decarboxylase –UROD- (E.C. 4.1.1.37) is the 5th enzyme of the haeme metabolic pathway. In all living organisms, haem importance is multiple because is the prosthetic group of different hemoproteins of significance (haemoglobin, haemocyanin, catalases, peroxidases and cytochromes). We have stared comparative studies between the enzyme coming from Wistar rat and from the hepatopancreas of the crab Chasmagnathus gralulatus. Optimum pH of each systems tends to its internal physiology pH, being 7.2 and 6.8 for crab and rat respectively. However, the optimum temperature was 47 ºC for both systems. From the Arrhenius grafic, the activation energy (Ae) was calculated. Ae for C. granulatus was 52,700 joules/mol while that for Wistar ratwas 8,900 joules/mol. (early stage of purification). The value obtained for crab is similar to that achieved for one of the two isoforms isolated from Wistar rat, suggesting that in C. granulatus exist only one enzymatic species.