Two thermally stable chitosanase isoforms were purified from the sheaths of chitosan-treated bamboo shoots. Isoforms A and B had molecular masses of 24.5 and 16.4 kDa and isoelectric points of 4.30 and 9.22, respectively. Using chitosan as the substrate, both isoforms functioned optimally between pH 3 and 4, and the optimum temperatures for the activities of isoforms A and B were 70 and 60 °C, respectively. The kinetic parameters K(m) and V(max) for isoform A were 0.539 mg/mL and 0.262 μmol/min/mg, respectively, and for isoform B were 0.183 mg/mL and 0.092 μmol/min/mg, respectively. Chitosans were susceptible to degradation by both enzymes and could be converted to low molecular weight chitosans between 28.2 and 11.7 kDa. Furthermore, the most susceptible chitosan substrates were 50-70 and 40-80% deacetylated for isoforms A and B, respectively. Both enzymes could also degrade chitin substrates with lower efficacy. N-Bromosuccinimide and Woodward's reagent K strongly inhibited both enzymes.

Three isoforms of peroxidase (POD) were isolated from the sheaths of bamboo shoots by chromatofocusing on Polybuffer exchanger PBE 94. POD-A was partially purified, and POD-B and POD-C were purified and characterised. POD-A was a basic peroxidase, whereas POD-B and POD-C were acidic peroxidases with different isoelectric points. Using o-phenylenediamine (OPD) as a hydrogen-donor, the optimum temperatures for function of POD-B and POD-C were 55 and 45-55°C, respectively, while both had the same optimum pH of 4.5. Both isoforms were stable between 30 and 60°C and between pH 4.5 and 10. The activities of the POD isoforms towards hydrogen-donors were both pH and concentration dependent. Under optimal conditions, POD-B and POD-C catalysed the oxidation of catechol, pyrogallol, and OPD at higher rates than guaiacol, o-dianisidine and 2, 2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid). Both isoforms were almost completely inhibited by chemical modification reagent diethyl pyrocarbonate (4.5 mM).

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