Abstract
In the previous report, one of the three lipase-activators isolated from Hizikia fusiformis has been identified as phytol, a terpene, and considered to be a new, typical activator, most effective among them. However, only triacetin has been thus far used as the substrate for testing the activator activity with the crude porcine pancreatic lipase. Hence, it was attempted to see which enzyme activity, so-called lipase or esterase, in the crude preparation is susceptible to the stimulation of phytol, by the use of various substrates and inhibitors.
A remarkable stimulation with phytol was observed only when the soluble substrates such as methyl butyrate and monopropionin as well as triacetin were employed, while no stimulation was observed when emulsions of insoluble substrates such as tributyrin and olive oil were employed.
The esterase activity thus stimulated by phytol was distinguishable from the lipase activity by the effect of DFP; the estrase activity and its stimulation were significantly inhibited by DFP, while none of the lipase activity was affected.
Thus, the enzyme activity susceptible to phytol stimulation was found not to be the typical lipase activity but the esterase activity in the crude preparation. Therefore, this stimulation by phytol should be added as a new differentiating feature between pancreatic lipase and esterase activities.
The addition of NaCl or pre-heating, of the enzyme at 60°C abolished the stimulation by phytol.
