Milleporin-1, a new phospholipase A"2 active protein from the fire coral Millepora platyphylla nematocysts [An article from: Comparative Biochemistry and Physiology, Part C]

This digital document is a journal article from Comparative Biochemistry and Physiology, Part C, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
Stings of fire corals, potent hydroids common in the Red Sea, are known to cause severe pain and they develop burns and itching that lasts few hours after contact. Nematocyst venom of Millepora platyphylla (Mp-TX) was isolated according to a recent method developed in our laboratory to conduct a previous investigation on the nematocyst toxicity of Millepora dichotoma and M. platyphylla. In this study, Mp-TX was fractionated by using both gel filtration and ion exchange chromatography. Simultaneous biological and biochemical assays were performed to monitor the hemolytic (using washed human red blood cells, RBCs) and phospholipase A"2 (using radiolabeled sn-2 C^1^4-arachidonyl phosphatidylcholine as a substrate) active venom fractions. The magnitude of both hemolysis and phospholipase A"2 activity was found in a fraction rich of proteins of molecular masses ~30,000-34,000 Daltons. The former fraction was purified by ion exchange chromatography, and a major bioactive protein factor (approx. 32,500 Daltons , here named milleporin-1) was recovered. Milleporin-1 enzymatic activity showed a significant contribution to the overall hemolysis of human RBCs. This activity, however, could not be completely inhibited using phospholipid substrates. Melliporin-1 fraction retained about 30% hemolysis, until totally rendered inactive when boiled for 3 min. The overall mechanism of action of milleporin-1 to impact the cellular membrane was discussed; however, it is pending more biochemical and pharmacological future studies.