Mutant/mutation
The mutant lacks expression of ALAS and expresses the reporters GFP-Luciferase and mCherry under a constitutive promoter

Protein (function)
The malaria parasite is capable of de novo heme biosynthesis despite its ability to acquire heme from red blood cell (RBC) hemoglobin. The first enzyme of the de novo heme-biosynthetic pathway, δ-aminolevulinate synthase (ALAS) and the last two enzymes, Protoporphyrinogen IX oxidase (PPO) and Ferrochelatase (FC) localize to the mitochondrion. The enzymes that catalyze the intermediate steps: ALA dehydratase (ALAD), Porphobilinogen deaminase (PBGD) and Uroporphyrinogen III decarboxylase (UROD) localize to the apicoplast whereas, the next enzyme Coproporphyrinogen III oxidase (CPO) is cytosolic. Earlier studies showed that host ALAS and FC are imported into the parasites in the intraerythrocytic stages, suggesting that the host machinery may augment parasite heme synthesis.
In Plasmodium ALAS is essential for development in the mosquito and in the liver but is not essential for blood stage growth/multiplication (see also RMgm-924)

Phenotype
ECM-susceptible C57BL/6 were by injected with 10(5) asexual stage parasites. Blood parasitemia showed 2–3 days delay in the growth of ALAS-KO parasites with respect to the wild type (WT). 
About 80% of the WT-infected mice succumbed to ECM within day 10 when the blood parasitemia was around 10–30%. In contrast, mice infected with ALASKO and FCKO parasites were protected from ECM and they died because of anemia on day 20–30. 

Additional information
Evidence is presented that:
- Decreased hemozoin (Hz) formation in heme pathway KO parasites
- De novo heme is essential for the functional integrity of food vacuole (FV) 

Other mutants