TABLE 1.

Biochemical characteristics of glycoside hydrolases encoded within the glucan degradation locus

Gene locus	Domains	No. of amino acids in protein	Predicted molecular mass (kDa)	Approx observed molecular massd (kDa)	Optimal temp (°C)	Optimal pH	Substratese	Specific activityc	Reference(s)
Athe_1867	GH9-CBM3-CBM3-CBM3-GH48	1,759	195	230	85	5–6.5	Glucans (Avicel, barley beta-glucan, CMC), xylan	On Avicel, 23–55 U/μmol; on barley beta-glucan, 100,510 U/μmol	13 – 15
Athe_1859	GH5-CBM3-CBM3-GH44	1,294	142	170	85	5	Glucans (PASC, CMC, Avicel, lichenin), mannans (guar gum, 1,4-β-mannan), glucomannan (konjac), xylan (birchwood), xyloglucan	On Avicel, 5.3 U/μmol	17
Athe_1857a	GH10-CBM3-CBM3-GH48	1,478	165	200	85–90	6.5	Xylan (beechwood), arabinoxylan (wheat), glucans (barley beta-glucan, lichenin, CMC, PASC, Avicel, filter paper), glucomannan (konjac), arabinans (arabic gum, debranched arabinan), pectin	On Avicel, 3.4 U/μmol; on beechwood xylan, 39,000 U/μmol; on barley beta-glucan, 3,400 U/μmol	19
Athe_1866b	GH5-CBM3-CBM3-CBM3-GH5	1,414	156	195	Not available	5.5–6.5	For N-terminal GH5, mannans; for C-terminal GH5, glucans (PASC)	Not available	17, 18
Athe_1865	GH9-CBM3-CBM3-CBM3-GH5	1,369	151	180	85–90	5.5–6.5	Glucans (Avicel, filter paper, PASC, lichenin), mannans (locust bean gum, guar gum), glucomannan (konjac), arabinoxylan (wheat), xylan (oat spelt)	On Avicel, 10.2 U/μmol; on locust bean gum, 1,691 U/mg	16, 18

^aGH10 only was characterized; the GH48 domain is 100% identical to that encoded by Athe_1867.

^bThe Athe_1866-encoded N-terminal GH5 domain is 100% identical to the Athe_1859-encoded GH5 domain.

^cEnzyme activity units are defined as micromoles of reducing sugar per minute.

^dObserved via SDS-PAGE (34; this study).

^eCMC, carboxymethyl cellulose; PASC, phosphoric acid-swollen cellulose.