Die Sekretion und Thermostabilität der Bakterienproteinasen.

Abstract

Young, rapidly reproducing cultures of B. fluorescens liquejaciens or B. subtilis secrete a proteinase. Centrifuged and washed cells of a 15 hr. culture contain only 0.4-0.6% of the proteolytic activity of the whole culture, but contain the whole of the poly-and dipeptidases, thus confirming the conception that the proteinase is a true secretion, not a product of autolysis. The proteinase is not inactivated at 100[degree] in 10 min. in the presence of proteins, but is lost in 30 min. at 60[degree] in protein free media. The protective action of proteins is minimal at 60[degree] but strong at 70[degree].