Purification and characterization of the biological effects of phospholipase A2 from sea anemone Bunodosoma caissarum

Sea anemones contain a variety of biologically active substances. Bunodosoma caissarum is a sea anemone from the Cnidaria phylum, found only in Brazilian coastal waters. The aim of the present work was to study the biological effects of PLA2 isolated from the sea anemone B. caissarum on the isolated perfused kidney, the arteriolar mesenteric bed and on insulin secretion. Specimens of B. caissarum were collected from the São Vicente Channel on the southern coast of the State of São Paulo, Brazil. Reverse phase HPLC analysis of the crude extract of B. caissarum detected three PLA2 proteins (named BcPLA21, BcPLA22 and BcPLA23) found to be active in B. caissarum extracts. MALDI-TOF mass spectrometry of BcPLA21 showed one main peak at 14.7 kDa. The N-terminal amino acid sequence of BcPLA21 showed high amino acid sequence identity with PLA2 group III protein isolated from the Mexican lizard (PA23 HELSU, HELSU, PA22 HELSU) and with the honey bee Apis mellifera (PLA2 and 1POC_A). In addition, BcPLA21 also showed significant overall homology to bee PLA2. The enzymatic activity induced by native BcPLA21 (20 μg/well) was reduced by chemical treatment with p-bromophenacyl bromide (p-BPB) and with morin. BcPLA21 strongly induced insulin secretion in presence of high glucose concentration. In isolated kidney, the PLA2 from B. caissarum increased the perfusion pressure, renal vascular resistance, urinary flow, glomerular filtration rate, and sodium, potassium and chloride levels of excretion. BcPLA21, however, did not increase the perfusion pressure on the mesenteric vascular bed. In conclusion, PLA2, a group III phospholipase isolated from the sea anemone B. caissarum, exerted effects on renal function and induced insulin secretion in conditions of high glucose concentration.