title: Purification, properties, and amino acid sequence of a hemoglobinuria-inducing phospholipase A(2), MiPLA-1, from Micropechis ikaheka venom.
abstract: Dark-colored urine is one of the clinical symptoms of envenomation by Micropechis ikaheka (New Guinea small-eyed snake). We have purified a phospholipase A(2), MiPLA-1, which induces dark-colored urine in experimental mice, to homogeneity. The analysis of the dark-colored urine by electrophoresis and N-terminal sequence determination indicated that the color of mouse urine is due to hemoglobin in the urine but not myoglobin. MiPLA-1 is the first hemoglobinuria-inducing toxin. Insignificant hemolytic activity of MiPLA-1 indicates that hemoglobinuria is not due to lysis of erythrocytes by MiPLA-1. This suggests that hemoglobinuria induced by MiPLA-1 may be due to kidney leakage caused by unknown mechanisms. MiPLA-1 also showed other biological effects, including myotoxicity as well as anticoagulant and antiplatelet effects. Structural studies show that MiPLA-1 is a basic protein with a molecular mass of 14041.60 +/- 1.78 as determined by electrospray mass spectrometry. We have determined the complete amino acid sequence of MiPLA-1. It is a 124-amino-acid protein with a "pancreatic loop" and belongs to group IB phospholipase A(2) enzymes. Two short segments flanked by proline brackets are found in the sequence of MiPLA-1. These segments are on the surface of the molecule and hence may be involved in protein-protein recognition.
authors.affiliation: Department of Anatomy, Faculty of Medicine, Faculty of Science, National University of Singapore, 10 Kent Ridge Crescent, Singapore, 119260, Singapore.
authors.forename: R
authors.initials: R
authors.lastname: Gao
authors.forename: R M
authors.initials: RM
authors.lastname: Kini
authors.forename: P
authors.initials: P
authors.lastname: Gopalakrishnakone
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology; D001777:Blood Coagulation / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D004546:Elapid Venoms / Q000737:chemistry* / Q000633:toxicity*; D017815:Elapidae; D054500:Group IB Phospholipases A2; D006456:Hemoglobinuria / Q000139:chemically induced*; D006461:Hemolysis / Q000187:drug effects; D007668:Kidney / Q000187:drug effects / Q000502:physiology; D007700:Kinetics; D051379:Mice; D008969:Molecular Sequence Data; D009512:New Guinea; D010741:Phospholipases A / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D010974:Platelet Aggregation / Q000187:drug effects*; D011517:Prothrombin Time; D030162:Reptilian Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D000925:Anticoagulants; D004546:Elapid Venoms; D030162:Reptilian Proteins; D010741:Phospholipases A; D054500:Group IB Phospholipases A2; D002118:Calcium