Purified elementary bodies of vaccinia have been tested with a variety of substrates and found to possess phosphatase, catalase, and lipase activity. Tests for malate, succinate, pyruvate, and lactate dehydrogenases were negative.
Interpretation of these results is complicated by the observation that elementary bodies of vaccinia adsorb relatively large quantities of certain enzymes from dilute solutions. These enzymes are not eluted by procedures of washing and centrifuging similar to those carried out in the preparation of the virus. For this reason, the presence of phosphatase, catalase, and lipase in the purified virus may well be accounted for on the basis of adsorption from the host tissues which are known to be rich in these particular enzymes. That some degree of specificity in this adsorption is to be recognized is shown by the failure of the virus to adsorb urease, an enzyme of vegetable origin.
Until some method can be devised which will distinguish between the enzymes of the host cell and those which may be integral parts of the virus it would seem that the problem of the enzyme constituents of vaccine virus is incapable of definite solution.