Aliquots of the filtered supernatan

Aliquots of the filtered supernatant (0.45-mm Millipore filter) of
an overnight culture were treated with catalase (1000 U ml1),
trypsin, actinase, protease XIII, ficin, trypsin from porcine pancreas,
a-chymotrypsin and pepsin at a final concentration of 10 IU/mg in
phosphate buffer (pH 7.0).