Why choline supplementation did not enhance phosphatidylcholine level in Candida albicans

In contrast to Saccharomyces cerevisiae cells, the supplementation of the growth media of Candida albicans cells with choline did not result in PC enrichment. The level of accumulation of choline uptake, which is the first step of its utilisation was found to be 50% higher in S. cerevisiae cells. However, the activity of choline kinase (EC 2.7.1.32), the first enzyme in CDP-choline pathway was identical between the two cell types. It appears that CTP: phosphocholine cytidylyl-transferase (EC 2.7.7.15) may be the regulatory enzymatic step in overall PC biosynthesis of C. albicans cells.