The activation of CTP: phosphocholine cytidylyltransferase from rat liver by polyunsaturated phospholipid.

Experimental evidence is reported that the addition in vitro of a polyunsaturated soybean phospholipid material (EPL) to a CTP:PC cytidylyltransferase preparation from rat liver (E.C. 2.7.7.15) produces noticeable stimulation of this enzymatic activity. Preincubation for different time intervals of EPL under air or oxygen further stimulates the activating effects. Little influence is exerted on the same enzyme by saturated lipids, such as dipalmitoyl-sn-glycero-3-phosphorylcholine and distearoyl-sn-glycero-3-phosphorylcholine. It is proposed that the lipid components of the EPL which exert the stimulatory action may be lyso-phospholipid moieties derived from EPL upon preincubation or directly present in the product. The biological significance of these activations in liver tissue is discussed.