ACTION OF VARIOUS ENZYMES ON THE MATING TYPE SUBSTANCES OF PARAMECIUM CALKINSI

¹ Osborn Zoological Laboratory, Yale University, New Haven, Conn.

1. In an attempt to characterize the mating type substances of Paramecium calkinsi, several enzymes were tested for ability to destroy the reactivity of formalinor picric acid-killed animals.

2. The following non-proteolytic enzymes had no detectable effect upon the mating reactivity of P. calkinsi: Lecithinase(bee venom), hyaluronidase, lysozyme, ptyalin, ribonuclease. Insofar as these experiments were critical, it is concluded that the natural substrates for these enzymes are not essential constituents of the mating type substance of P. calkinsi.

3. Crystalline preparations of the proteolytic enzymes trypsin and chymotrypsin destroyed the mating reactivity of both type I and type II animals. Mating substance activity was not found in the digest of enzyme-treated paramecium.

4. On the basis of these findings it is concluded that mating reactivity is dependent upon protein integrity. Possibilities regarding the nature of this dependence are discussed.