Multiple types and forms of odorant-binding proteins in the Old-World porcupine Hystrix cristata.

1. Eight new proteins have been identified and purified from the nasal tissue of the old-world porcupine. 2. All of them show good binding activity to tritiated 2-isobutyl-3-methoxypyrazine. 3. They show values of molecular mass, in denaturing conditions, between 18 and 23 kDa, and of isoelectric points between 4.2 and 4.6. 4. This represents the first example of more than two odorant-binding proteins (OBPs) found in the same animal species and could support a discriminating function of these proteins in the process of odour perception.