| IED ID | IndEnz0002008309 |
| Enzyme Type ID | protease008309 |
| Protein Name |
Plasmepsin I EC 3.4.23.38 Aspartic hemoglobinase I Plasmepsin 1 |
| Gene Name | PMI |
| Organism | Plasmodium falciparum (isolate HB3) |
| Taxonomic Lineage | cellular organisms Eukaryota Sar Alveolata Apicomplexa Aconoidasida Haemosporida (haemosporidians) Plasmodiidae Plasmodium Plasmodium (Laverania) Plasmodium falciparum Plasmodium falciparum (isolate HB3) |
| Enzyme Sequence | MALSIKEDFSSAFAKNESAVNSSTFNNNMKTWKIQKRFQILYVFFFLLITGALFYYLIDNVLFPKNKKINEIMNTSKHVIIGFSIENSHDRIMKTVKQHRLKNYIKESLKFFKTGLTQKPHLGNAGDSVTLNDVANVMYYGEAQIGDNKQKFAFIFDTGSANLWVPSAQCNTIGCKTKNLYDSNKSKTYEKDGTKVEMNYVSGTVSGFFSKDIVTIANLSFPYKFIEVTDTNGFEPAYTLGQFDGIVGLGWKDLSIGSVDPVVVELKNQNKIEQAVFTFYLPFDDKHKGYLTIGGIEDRFYEGQLTYEKLNHDLYWQVDLDLHFGNLTVEKATAIVDSGTSSITAPTEFLNKFFEGLDVVKIPFLPLYITTCNNPKLPTLEFRSATNVYTLEPEYYLQQIFDFGISLCMVSIIPVDLNKNTFILGDPFMRKYFTVFDYDNHTVGFALAKKKL |
| Enzyme Length | 452 |
| Uniprot Accession Number | P39898 |
| Absorption | |
| Active Site | ACT_SITE 157; /evidence=ECO:0000255|PROSITE-ProRule:PRU10094; ACT_SITE 337; /evidence=ECO:0000255|PROSITE-ProRule:PRU10094 |
| Activity Regulation | ACTIVITY REGULATION: Inhibited by pepstatin A. {ECO:0000269|PubMed:8844673}. |
| Binding Site | |
| Calcium Binding | |
| catalytic Activity | CATALYTIC ACTIVITY: Reaction=Hydrolysis of the 33-Phe-|-Leu-34 bond in the alpha-chain of hemoglobin, leading to denaturation of molecule.; EC=3.4.23.38; Evidence={ECO:0000269|PubMed:2007860, ECO:0000269|PubMed:8313875, ECO:0000269|PubMed:8844673}; |
| DNA Binding | |
| EC Number | 3.4.23.38 |
| Enzyme Function | FUNCTION: During the asexual blood stage, catalyzes the initial cleavage of native host hemoglobin (Hb) resulting in Hb denaturation; specifically cleaves between Phe-33 and Leu-34 of Hb alpha-chain (PubMed:8313875, PubMed:2007860, PubMed:8844673). Digestion of host Hb is an essential step which provides the parasite with amino acids for protein synthesis, and regulates osmolarity (Probable). {ECO:0000269|PubMed:2007860, ECO:0000269|PubMed:8313875, ECO:0000269|PubMed:8844673, ECO:0000305}. |
| Temperature Dependency | |
| PH Dependency | BIOPHYSICOCHEMICAL PROPERTIES: pH dependence: Optimum pH is 4.5-5. {ECO:0000269|PubMed:2007860}; |
| Pathway | |
| nucleotide Binding | |
| Features | Active site (2); Beta strand (24); Chain (1); Disulfide bond (2); Domain (1); Helix (8); Propeptide (1); Topological domain (2); Transmembrane (1); Turn (6) |
| Keywords | 3D-structure;Aspartyl protease;Direct protein sequencing;Disulfide bond;Hydrolase;Membrane;Protease;Reference proteome;Signal-anchor;Transmembrane;Transmembrane helix;Vacuole;Zymogen |
| Interact With | |
| Induction | |
| Subcellular Location | SUBCELLULAR LOCATION: Membrane {ECO:0000269|PubMed:9169469}; Single-pass type II membrane protein {ECO:0000269|PubMed:9169469}. Vacuole lumen {ECO:0000269|PubMed:11782538, ECO:0000269|PubMed:2007860, ECO:0000269|PubMed:8313875, ECO:0000269|PubMed:9169469}. Vacuole membrane {ECO:0000305|PubMed:9169469}. Note=At the beginning of the asexual blood stage, the transmembrane zymogen is transported to the cytostome, an endocytic structure spanning the parasite cell membrane and the parasitophorous vacuole membrane where host proteins such as hemoglobin are endocytosed (PubMed:9169469). Following endocytosis, localizes to the cytostome vacuole membrane to be then delivered to the digestive (or food) vacuole where it is cleaved into the soluble and active enzyme (PubMed:9169469). In trophozoites, localizes to the digestive vacuole, an acidic vacuole where host hemoglobin is digested (PubMed:8313875, PubMed:9169469). {ECO:0000269|PubMed:8313875, ECO:0000269|PubMed:9169469}. |
| Modified Residue | |
| Post Translational Modification | PTM: Not N-glycosylated. {ECO:0000269|PubMed:9169469}.; PTM: Proteolytically cleaved into the soluble active mature form in the digestive vacuole by cysteine protease falcipains; the process begins at the early ring stage (PubMed:9169469, PubMed:12850260). Proteolysis requires an acidic environment (PubMed:9169469, PubMed:12850260). {ECO:0000269|PubMed:12850260, ECO:0000269|PubMed:9169469}. |
| Signal Peptide | |
| Structure 3D | X-ray crystallography (2) |
| Cross Reference PDB | 3QRV; 3QS1; |
| Mapped Pubmed ID | - |
| Motif | |
| Gene Encoded By | |
| Mass | 51,461 |
| Kinetics | |
| Metal Binding | |
| Rhea ID | |
| Cross Reference Brenda | 3.4.23.38; |