Table 1. Chitinolytic activities of Pseudomonas chitinase C (PsChiC) expressed in E. coli.

Sample	Protein	Chitinolytic activity (units/mg of protein)
		Endochitinase*	Chitobiosidase	Exochitinase
E. coli without vector	Secreted	0.00 ± 0.00d	0.05 ± 0.01c	0.01 ± 0.01b
E. coli with pET-PsChiC	Secreted	63.02 ± 0.11b	21.33 ± 0.07b	0.01 ± 0.01b
E. coli with pET-PsChiC	Intracellular	34.42 ± 0.32c	10.47 ± 0.04b	0.02 ± 0.01b
Pseudomonas sp. TXG6-1	Secreted	15.26 ± 0.94a	8.55 ± 0.66a	1.73 ± 0.13a

The data are expressed as the mean ± SD. Values with the same letter were not significantly different as determined by Tukey’s multiple range test (p < 0.05).

^*The substrates used for the enzymatic assays were: p-nitrophenyl N,N′-diacetyl-β-D-chitobioside (chitobiosidase activity), p-nitrophenyl N-acetyl-β-D-glucosaminide (exochitinase activity) and 4-nitrophenyl β-D-N,N′,N″-triacetylchitotriose (endochitinase activity). In all cases, formation of the reaction product (p-nitrophenol), which ionizes in basic pH, was monitored colorimetrically at 405 nm.