Studies on the Biosynthesis of Extracellular Proteases by Bacteria

Abstract

The occurrence of proteolytic activity in ceU-free culture filtrates of some bacteria has given rise to many discussions on the question of whether the presence of proteins or protein derivatives is necessary for the protease formation. Haines (7) reviewed the literature on this subject up to 1931, and based on his own experimental results, concluded that proteases were formed in well grown cultures in simple synthetic media with an inorganic source of nitrogen provided that magnesium and calcium salts were present; the first mentioned would stimulate growth and the latter the protease formation (8). Gotini el a/. (4-6) studied the effect of calcium on the proteinases produced by several bacteria cultivated in nutrient agar and reached the conclusion that it was not essential for the protease formation but only for the function and stability of the enzyme. They supposed that the active form of the bacterial protease was a calcium-protein complex.In this paper evidence is presented (1) that Serratia marcescens proteinase was not found, at least in active form, in a synthetic medium with or without calcium provided that care was taken to avoid high concentrations of bacterial mass; and (2) that carefully washed bacteria from a proteolyticaUy inactive culture in the synthetic medium placed in an aqueous solution of gelatin showed activity after a short period of time. Materiels and MethodsSerratia n~rcescens.--Straln 9986 from the American Type Culture Collection. Synthet/c Med/a.mComposition described at the foot of Table I. Cu/ti~ion.mThe original strain was inoculated on plates of standard synthetic medium solidified with agar and incubated for 21 hours at 29°C. Then the surfaces were washed with sterile saline solution (0.125 ,~ NaC1), and the resulting bacterial suspension collected, centrifuged, and washed twice under sterile conditions. Finally the bacteria were suspended again and by suitable dilution, 10 s cells were inoculated * A preliminary report of cer~in phases of this work was presented at

Extracellular Proteases in Erwinia chrysanthemi

“…This activity appeared when the cells were grown in the presence of peptides, but not in the presence of a mixture of amino acids, indicating that intact peptide bonds are involved in the induction process, as already reported for proteolytic enzymes produced by Serratia marcescens (Braun & Schmitz, 1980;Bromke & Hammel, 1979;Castaneda-Agullo, 1956) and various Vibrio species (Dreisbach & Merkel, 1978;Keil- Dlouha et a f . , 1976).…”

Purification and Partial Characterization of a Bacteriocin from Serratia marcescens

“…The cell pellet, 150 to 200 g (wet weight), was chilled in an ice bath, and from this point all operations were performed at 0 to 4 C. Figure 1 shows the appearance of bacteriocin JF246 activity in the culture after addition of mitomycin C. When the culture was allowed to incubate longer than 2.5 hr in the presence of mitomycin C, a dramatic decrease in bacteriocin titer occurred. This was presumably due to destruction of the bacteriocin by an extracellular protease produced by Serratia (2).…”

Isolasi Bakteri Termofilik Sumber Air Panas Gedongsongo dengan Media Pengaya MB (Minimal Broth) dan TS (Taoge Sukrosa) serta Identifikasi Fenotip dan Genotip

“…Tabung tersebut kemudian dimasukkan ke dalam lemari es selama 24 jam. Aktivitas enzim protease ditunjukkan dengan tetap mencairnya larutan setelah didinginkan [18].…”