A polysaccharide utilization locus from Flavobacterium johnsoniae enables conversion of recalcitrant chitin

Table 2 Summary of catalytic parameters for the ChiUL enzymes

Enzyme	Substrate	k _cat (s⁻¹)	K _m (mM)	k _cat /K _m (mM⁻¹ s⁻¹)
ChiA_N	Chitotriose	0.12 ± 0.007	4.0 ± 0.4	0.031
	Chitotetraose	17.4 ± 0.65	0.050 ± 7.3 × 10⁻³	349
	Chitopentaose	20.7 ± 0.93	0.017 ± 3.9 × 10⁻³	1190
	Chitohexaose^a	48.8 ± 6.1	0.051 ± 0.012	951
ChiA_C	Chitotriose	0.014 ± 6.0 × 10⁻⁴	1.17 ± 0.15	0.012
	Chitotetraose	0.99 ± 0.03	1.11 ± 0.08	0.89
	Chitopentaose	1.66 ± 0.047	0.15 ± 0.02	11.1
	Chitohexaose	1.29 ± 0.022	0.071 ± 3.5 × 10⁻³	18.3
ChiB	Chitotriose	0.39 ± 0.014	5.6 ± 0.40	0.069
	Chitotetraose^a	9.77 ± 1.56	2.2 ± 0.45	4.4
	Chitopentaose^a	19.9 ± 1.48	0.40 ± 0.052	49.4
	Chitohexaose^a	60.1 ± 7.4	0.45 ± 0.08	135
GH20	Chitobiose	164 ± 10	0.83 ± 0.13	198
	Chitotriose	113 ± 6.8	0.65 ± 0.11	175
	Chitotetraose	106 ± 4.1	0.66 ± 0.072	162
	Chitopentaose	104 ± 2.8	0.61 ± 0.048	170
	Chitohexaose	94.2 ± 4.1	0.51 ± 0.066	183

Values represent means and standard errors from duplicate experiments
Data were fitted to the Michaelis–Menten or substrate inhibition equations (v _o = V _max*[S]/(K _m + [S] × (1 + [S]/K _i)))
^aReactions for which substrate inhibition was observed

ISSN: 2731-3654