Occurrence of a complex form of staphylokinase in the course of cultivation of Staphylococcus aureus.

Proteins in the culture supernatant of Staphylococcus aureus PS 47 were subjected to Sephadex chromatography. In the early stage of the cultivation, staphylokinase appeared to have a molecular weight of 15,000 and in the later stage it appeared to have a molecular weight of 320,000. The staphylokinase having a lower molecular weight (type A) converted into one having a higher value (type B) during the course of cultivation. It was demonstrated that conversion of type A into type B took place in vitro (monitored by gel filtration after the two types of staphylokinases were mixed), and it was observed that type B reverted to type A when type B was treated with KCl or detergent. Type B seems to be a complex form of type A and some high-molecular-weight substance.