Fig. 4.

Substrate affinity of Spr Cel8A and effect of metal ions and other agents on enzyme activity. (a) The activity of Spr Cel8A was assayed using Avicel, CMC, Solka Floc, beechwood xylan, birchwood xylan, and oat spelt xylan as the substrate, at a final concentration of 0.5 % each in 50 mM citrate phosphate buffer, pH 7.0 at 40 ºC. (b) Effect of metal ions, EDTA and 2-ME on Spr Cel8A activity at two different concentrations 1 and 5 mM. Enzyme was incubated in 0.5 % (w/v) CMC in 50 mM citrate sodium phosphate buffer, pH 7.0 containing (1 and 5 mM each): Ca²⁺, Co²⁺, Mn²⁺, Ni²⁺, Mg²⁺, Fe²⁺, Cu²⁺, Na¹⁺, Zn²⁺, Li¹⁺, and Hg²⁺; EDTA and 2-ME at 28 ºC for 60 min. All tests were performed in triplicate and error bars indicate standard deviations