DISTINCT BOTHROJARACIN ISOFORMS PRODUCED BY INDIVIDUAL JARARACA (BOTHROPS-JARARACA) SNAKES

Bothrojaracin (apparent mel. wt 27,000) is a potent inhibitor of throm bin previously isolated from the venom of Bothrops jararaca. Several m olecular variants (isoforms) have been identified in a pool of venom c ollected from a large number of animals. In order to determine whether an individual snake produces a single type of bothrojaracin or multip le isoforms, we analyzed the bothrojaracin content of venoms collected individually from six adult B. jararaca snakes. Bothrojaracin was fou nd in all venoms, but its activity was especially high in three of the m. After purification on an alpha-thrombin affinity column, followed b y gel filtration on Superose 12 HR, proteins from these three venoms m igrated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis a s single bands of 27,000 and their amino-terminal sequences (residues 1-28) revealed extensive homology with bothrojaracin. In contrast, the material purified from the three venoms with low bothrojaracin activi ty consisted of bothrojaracin together with inactive proteins. Differe nces in the sequences obtained for bothrojaracin isolated from individ ual venoms indicated the existence of more than one isoform in the ven om of an individual snake. (C) 1997 Elsevier Science Ltd.