Effects of class-specific proteinase inhibitors on
the FITC-casein-hydrolyzing activities of extracts from 6-, 18-, and
30-month-old tubers. FITC-casein was added to tuber extracts containing
each inhibitor and hydrolysis was assessed after 60 min of incubation
at 37°C. Spectrofluorometric units are emission at 520 nm following
excitation at 500 nm. Proteinase inhibitors include PMSF and AEBSF
(Ser-type), E-64 and leupeptin (Cys-type), pepstatin (Asp-type),
and EDTA (metallo-type). Data are averages ± se of
three replicates. Numbers in bars are percent inhibition relative to
control (no inhibitors present).