Kinetic modelling of phospholipid synthesis in Plasmodium knowlesi unravels crucial steps and relative importance of multiple pathways

Table 1 List of reactions and metabolites in the network

Reaction ID	Substrates & products	Enzyme (E.C number)	ORF (P.falciparum/P.knowlesi)	References
R1	SerE → Ser	?	?	[28]
	(Serine transport)
R2	Ser → PS	PSS	(MAL8P1.58) /(PKH_051100)	Vial (unpublished data).
	(Phosphatidylserine synthesis)		predicted
R3	Ser → Etn	SD	?	[28]
	(Serine decarboxylation)	4.1.1
R4	Etn → PEtn	EK	PfEK	[29]
	(Ethanolamine phosphorylation)	2.7.1.82	(PF11_0257) /(PKH_092210)
R5	PEtn → PCho	PMT	PfPMT	[30, 31]
	(Phosphoethanolamine methylation)	2.1.1.103	(MAL13P1.214) / (PKH_121150)
R6	PS → PE	PSD	PfPSD	[32]
	(Phosphatidylserine decarboxylation)	4.1.1.65	(PFI1370c) /(PKH_072580)
R7	PEtn → PE	ECT	PfECT	[28, 33]
		2.7.7.14	(PF13_0253)/ (PKH_120620)
		CEPT/EPT	PfCEPT
		2.7.8.1	(PFF1375c)/(PKH_112100)
R8	PCho → PC	CCT	PfCCT	[33–35]
		2.7.7.15	(MAL13P1.86)/(PKH_141580)
		CEPT/CPT	PfCEPT
		2.7.8.2	(PFF1375c)/(PKH_112100)
R9	PE → PC	PEMT/PLMT	?	[28, 36, 37]
	(Methylation)	2.1.1.17/2.1.1.71
R10	PC → PS	PSSbe	(MAL13P1.335) /(PKH_110380)
	(base exchange)	2.7.8
R11	PE → PS	PSSbe	(MAL13P1.335) /(PKH_110380)
	(base exchange)	2.7.8		Berry and Vial (unpublished data)
R12	PC →	?	?
	(Phosphatidylcholine efflux)
R13	PS →	?	?
	(Phosphatidylserine efflux)
R14	PE →	?	?
	(Phosphatidylethanolamine efflux)
R15	ChoE → Cho	NPP/OCT/CTL	(PFE0825w) /(PKH_101630)	[20, 38–40]
	(Choline transport)
R16	Cho → PCho	CK	PfCK	[29, 41]
	(Choline phosphorylation)	2.7.1.32
R17	EtnE → Etn		?
	(Ethanolamine diffusion)

We have used the following abbreviations. SerE = exogenous serine, Ser = intracellular serine, PS = phosphatidylserine, EtnE = exogenous ethanolamine, Etn = intracellullar ethanolamine, PEtn = phosphoethanolamine, PE = phosphatidylethanolamine, ChoE = exogenous choline, Cho = intracellular choline, PCho = phosphocholine, PC = phosphatidylcholine, DAG = diacylglycerol, SD = serine decarboxylase, PSSbe = phosphatidylserine synthase I, PMT = phosphoethanolamine-N-methyltransferase, PEMT = phosphophatidylethanolamine-N-methyltransferase, CCT = cholinephosphate cytidylyl transferase, ECT = ethanolaminephosphate cytidylyl transferase, CEPT = choline/ethanolamine phosphotransferase, CK = choline kinase, EK = ethanolamine kinase, NPP = New permeation pathway, OCT = Organic cationic transporter, ? = putative genes found.
This model was deposited in BioModels Database [42] and assigned the identifier MODEL1310130000.

ISSN: 1752-0509