Catalytic antibodies (abzymes) which hydrolyze
RNA and
DNA were isolated from bovine colostrum by sequential chromatography on
Protein A Sepharose, denaturated
DNA-cellulose,
Mono Q, and gel permeation chromatography on
Superose 12 at pH 2.3 after acidic
shock. Metachromatic
agar containing
toluidine blue and yeast
RNA was used to measure
RNase activity. Electrophoresis in
agarose showed
DNase activity on plasmid
DNA from Escherichia coli and
DNA from calf thymus in fractions from all 4 purification steps. Gel permeation chromatography showed that the abzymes hydrolysed both a single-stranded polyadenylic
acid (
Poly A) and single-stranded polycitidylic
acid (
Poly C), while partially purified
RNase from the colostrum hydrolysed
Poly (C), but not
Poly (A). Electrophoresis of purified abzymes under denaturing conditions showed
protein bands of molecular mass corresponding to heavy and light chains of
IgG. The abzymes immunoreacted with anti-bovine
IgG. The
RNase activity of the purified abzymes represented 0.022% of total
RNase activity in the colostrum;
acid shock and gel filtration at low pH reduced the specific
RNase activity of abzymes 3.6-fold. The
RNase activity of abzymes at pH 6.6 was reduced by 90% by heat treatment at 75 degrees C for 52 min.