Partial Purification and Some Characteristics of Proteinase(s) Induced by Staphylococcal Exfoliative Toxin

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Abstract
After 8 hrs incubation with epidermis of newborn mice and exfoliative toxin, a marked increase in caseinolytic activity was detected, which reached a maximum at 12 hrs. Casein-hydrolyzing enzyme(s) induced by ET were partially purified by chromatography. A substantial increase in caseinolytic activity was detected in the fractions obtained from Sephadex G-50, while practically no caseinolytic activity was observed when the extract obtained from the epidermis incubated without ET was applied. The caseinolytic activity appeared as a single peak eluted from DEAE-Sepharose CL-6B and Sephadex G-75. However, on SDS-PAGE, the partially purified fractions exhibited several protein bands. The molecular weights of these band were estimated as 78 KD, 68 KD, 45 KD, 14.5 KD and 8.8 KD. When the partially purified enzyme(s) was preincubated with EGTA or EDTA, substantial inhibition of the activity was observed; however, no recovery of the activity was detected after the addition of CaCl2. Treatment of the enzyme(s) with PMSF and NEM caused little inactivation of the activity. Enzyme activity retained about 57% of the initial activity following 3 min incubation at 60 degrees C, but was completely inactivated after 4 min.