On the isolation of oöcytase,the fertilizing and cytolyzing substance in mammalian blood-sera. (Preliminary report.)

Abstract

It has been observed by Loeb that the eggs of sea-urchins (Strongylocentrotus purpuratus) may be induced to form fertilization-membranes by immersing them in mammalian blood-sera which have been rendered isotonic with sea-water by the addition of NaCl. Occasionally, if the serum be especially potent, simple immersion of the eggs in the serum suffices to bring about this result, but as a rule previous treatment of the eggs with a sensitizing agent (SrCl₂ or CaCl₂) is required. Prolonged action of the serum upon sensitized eggs results in the cytolysis of the eggs. Very potent sera usually cause agglutination of the eggs as well, especially of sensitized eggs.

I have isolated from ox-serum a fraction which is extremely potent in fertilizing, cytolyzing, and agglutinating sea-urchin eggs.

To 860 c.c. of fresh, whipped, and centrifugalized ox-serum, which had been rendered isotonic with sea-water by the addition of 2½M NaCl solution, I added 400 c.c. of 7 per cent. BaCl₂. A thick cloud was produced. This mixture after standing for an hour in a warm place until its temperature rose to 37° C. was centrifugalized. The entire precipitate, consisting of BaCO₃, BaSO₄, and the barium compound of the fertilizing agent and, possibly, of other substances, settled in the form of a cake at the bottom of the centrifuge-tubes. This precipitate was thoroughly drained and then suspended several times in 2 per cent. BaCl₂ and re-centrifuged in order to free it from adherent serum. It was then stirred up for an hour in IOO C.C. of N/10 HCl and the insoluble residue (probably barium sulphate) was centrifuged out. To the clear fluid thus obtained were added 10 C.C. of 10 per cent. Na₂S0₄ in order to free it from barium.