Specificity of Phospholipase D for Alcohol Substrate in Transphosphatidylation

The alcohol specificity of phospholipase D prepared from fresh cabbege leaves was evaluated by transphosphatidylation between phosphatidylcholine (PC) and 22 different alcohols, which were not only primary, secondary, and tertiary alcohols having different carbon numbers, but also mono-, di-, and trihydric alcohols differing in carbon length.Based on conversion ratios of PC to corresponding phosphatidylalcohols at less than 0.04 M alcohol in the water layer, the enzyme activity of which was not inhibited by any alcohol, the specificity of phospholipase D in transphosphatidylation was clearly shown not to be affected by carbon length.The ratios of primary monohydric alcohols were essentially the same as those of primary dihydric alcohols with the same carbon length, although the ratio of trihydric alcohol was less than that of any monohydric or dihydric alcohol. For monohydric alcohols having the same carbon number, primary alcohols were incorporated more easily into PC than secondary alcohols, but no tertiary alcohols were incorporated at all.Primary hydroxyl groups transfered more readily than secondary hydroxyl groups when using dihydric alcohols with the same carbon number.