Comparative Study of Thiaminase in Headfootand Hepatopancreas of Limicolaria flammea(M??ller, 1774)

摘要

Aims: This study aimed at determining the level of thiaminase in the Limicolaria flammea with a view to ascertaining the nutritional and health implications of its consumption.Methodology: Proximate analyses of two tissues, headfoot and hepatopancreas, were investigated to assess their nutritional qualities. The thiaminases in the tissues were purified by chromatographic separations using DEAE-Sephacel ion - exchange and Biogel P-100 columns. Results: The Michealis Menten constant obtained for hepatopancreas thiaminase was 0.83 mM and 0.13 mM for thiamine and aniline respectively; for the headfoot thiaminase, 1.06 mM and 0.16 mM was obtained for thiamine and aniline respectively. An optimum pH of 8.5 was obtained for thiaminase in the two tissues. Temperature optimum of 65°C and 70°C was obtained for the headfoot and hepatopancreas enzymes respectively. The amino acids and glutathione activated the enzyme from hepatopancreas, while the headfoot enzyme was significantly inhibited except proline which showed very high activation. The cations: NH4+, Hg2+, Mn2+, Na+, Ni2+, and Zn2+ tested showed no inhibition of the enzymes in both tissues. Increased concentrations of 2-mercaptoethanol, 6-amino hexanoic acid and ethylenediaminetetraacetic acid (EDTA) inhibited the activities of thiaminases from the two tissues.Conclusion: The study concluded that the tissues, hepatopancreas and headfoot of Limicolaria flammea contained high level of thiaminase. This may have medical implication in its consumption as a good source of high quality protein.