engleski

Partial purification and biochemical characterization of alkaline 5'-phosphodiesterase from barley malt sprouts

An alkaline 5'-phosphodiesterase (5'-PDE) from barley (Hordeum distichum) malt sprouts was partially purified by thermal treatment and acetone precipitation to diminish phosphomonoesterase (PME) activity. 5'-PDE was purified 40-fold to a specific activity of 30 U mg^-1 protein with a final yield of about 32%. With synthetic substrate, the enzyme had an optimum pH of 8.9, maximum activity at 70 ^oC over 10 min, and a Km of 0.26 mM. The partially purified enzyme was activated by 10 mM Mg^2+ up to 168% of the original activity, while Zn^2+, Mn^2+ and Cu^2+ ions, chelating agent (EDTA) and NaN_3 (1-10 mM), and 5'-ribonucleotides (1-5 mM) were inhibitory. Final enzyme preparation was stable over 8 d at 4 ^oC), at 70 ^oC for up to 120 min and without loss of activity over 90 d at -18 ^oC.

alkaline 5'-phosphodiesterase ; barley malt sprouts ; 5'-ribonucleotides ; storage stability ; thermostability

nije evidentirano