Table 1.

Specific activity (U/mg) against colloidal chitin and synthetic substrates of CvChi45

Substrate	CvChi45	S. griseus chitinase
Colloidal chitin*	22,260.5	20,368.0
p-nitrophenyl-N-acetyl-β-D-glucosamine (pNP-GlcNAc)**	ND	ND
p-nitrophenyl-β-D-N,N’-diacetylchitobiose [pNP-(GlcNAc)2]**	32,320.0	10,370.0
p-nitrophenyl-β-D-N,N’,N”-triacetylchitotriose [pNP-(GlcNAc)3]**	31,560.0	9,120.0

The specific activity (U/mg) of the purified chitinase was measured using colloidal chitin and synthetic substrates as described in the Methods section. A chitinase from Streptomyces griseus (Sigma) was included for comparison.

* For assays using colloidal chitin as the substrate (0.5% final concentration), one unit was defined as the amount of enzyme that released 1 nmol of GlcNAc/mg/h at 37°C.

** For assays using synthetic substrates, one unit was defined as the amount of enzyme that released 1 nmol of 4-nitrophenol/mg/h at 37°C; the substrates were assayed at final concentrations of 2.9 mM (pNP-GlcNAc), 1.8 mM [pNP-(GlcNAc)₂], and 1.3 mM [pNP-(GlcNAc)₃]; ND: not detected.