Phospholipase A 2 from Trypanosoma brucei gambiense and Trypanosoma brucei brucei : Inhibition by Organotins

Protozoology Department, Institute of Tropical Medicine, Nagasaki University, Japan.
Journal of enzyme inhibition 12/2001; 16(5):433-41. DOI: 10.1080/14756360109162392
Source: PubMed


Activity and kinetics of phospholipase A2 (PLA2) from Trypanosoma brucei gambiense (Wellcome strain) and Trypanosoma brucei brucei (GUTat 3.1) were examined using two different fluorescent substrates. The activity in the supernatants of sonicated parasites was Ca2+-independent, strongly stimulated by Triton X-100 with optimum activity at 37 degrees C and pH 6.5-8.5. To encourage a possible interaction between the parasite enzyme and organotin compounds, fatty acid derivatives of dibutyltin dichloride were synthesized and evaluated as potential inhibitors of PLA2. The enzyme from the two-trypanosome species differ with respect to kinetic parameters and are noncompetitively inhibited by the organotin compounds. The Michaelis constant (KM) for PLA2 from T. b. brucei is 63.87 and 30.90 microM while for T. b. gambiense it is 119.64 and 32.91 microM for the substrates 1,2-bis-(1-pyrenebutanoyl)-sn-glycero-3-phosphocholine (PBGPC) and 2-(12-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)dodecanoyl-1-hexadecanoyl-sn-glycero-3-phosphocholine (NBDC12-HPC), respectively.

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    • "Although PLA2 activity was detected in T. brucei, T. congolense, T. cruzi, L. major, and L. amazonensis years ago, still little is known about the identity of the genes that codify for them [36, 55, 56, 61, 63, 83]. We have performed a search in the TriTrypDB database and identified at least 9 putative PLA2-like proteins in the different Trypanosomes species (Table 1), but at the moment no PLA2 of trypanosomal origin has been identified in the genomes or cloned. "
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