Colicine K. I. The production of colicine K in media maintained at constant pH.

An apparatus for maintaining the pH of an actively growing bacterial culture at constant level has been described. Using this apparatus it has been shown that the production of maximal amounts of colicine K from a strain of E. coli known as K235 is dependent upon an enriched nutrient medium which is maintained at pH 7.

An electrophoretic study of a streptococcal proteinase and its precursor.

An electrophoretic study of crystalline preparations of a streptococcal proteinase and its precursor established their isoelectric points at pH values of 8.42 and 7.35 respectively (ionic strength 0.