The studies on the incubation of the reaction mixture at different temperatures
showed that formation of t-CA was maximal when the PAL forward reaction was carried
out at 37 ºC, and nearly identical activity was obtained at 42 ºC it can be
concluded that the IL environment is influencing thermostablity of the enzyme to a
certain extent (Fig. 4). Therefore, our results on effect of temperature on PAL activity are
consistent with earlier studies which have reported that the thermostability of enzymes is
increased in an IL environment [5-7].
In order to ensure maximum contact between enzyme and substrate, proper mixing of
the ingredients of the incubation mixture is necessary; and we observed that moderate
shaking (100 rev min-1) on a temperature controlled orbital rotator was sufficient for this
purpose. The yield of t-CA at various speeds of agitation is summarized in Table 2. As
the speed of agitation was increased to over 100 rev min-1, the enzyme activity was
reduced; this could be attributed to progressive denaturation of the enzyme on increased
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agitation. These results correspond well with studies on effect of agitation on PAL
protein; optimal enzymatic conversions have been obtained at ~50 – 100 rpm