Studies on lysophospholipases. VIII. Immunochemical differences between two lysophospholipases from beef liver.

1. Two distinct lysophospholipases have previously been obtained in homogeneous form from beef liver. In this paper, we demonstrate that ageing of a beef liver homogenate does not result in a change in the ratio of the two enzymatic activities, indicating that no interconversion of the lysophospholipases took place. 2. Possible partial structural relationships between the two enzymes were explored by immunochemical techniques. Rabbit antisera raised against each individual lysophospholipase showed no cross-reactivity with the other enzyme. This was concluded from immuno double-diffusion experiments and from the results of immunoprecipitation of enzymatic activities in solution. 3. Lysophospholipase and esterase activity in the purified preparation of lysophospholipase II from beef liver were concomitantly precipitated by anti-serum against lysophospholipase II. This is further proof that both enzymatic activities reside in a single polypeptide chain, in agreement with previous results of isoelectric focusing experiments.