Endoglucanase with high activity on carboxymethylcellulose (CMC) and lichenan, but not active on Avicel. Endohydrolysis of (1->4)-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans. Strongly inhibited by Hg(2+), Ag(+) and Fe(3+). To a lesser extent, is also inhibited by Pb(2+), Mn(2+), Sn(2+) and Cu(2+). By contrast, Ni(2+), Zn(2+), Co(2+), Ba(2+) and NH(4)(+) do not affect enzyme activity, while 10 mM Ca(2+), and Mg(2+) produce a stimulating effect. Is also strongly inhibited by chemicals such as N-bromosuccinimide and dimethyl(2-dihydroxy-5-nitrobenzyl)sulphonium bromide. Is not affected by N-acetylimidazole. Optimum pH is 4.0. Highly stable at acid pH. Retains 100% of its activity after 90 minutes incubation at pH 4.5 and 45 degrees Celsius, and 95% of the initial activity is found after 15 days incubation at room temperature and pH 4.5. Optimum temperature is 40 degrees Celsius. Shows 98% and 51% of its maximum activity at 45 and 55 degrees Celsius, respectively. Study of the performance of endoglucanase A on paper manufacture from agricultural fibers shows that treatment with the enzyme improves the properties of the pulp and the quality of paper. CelA treatment enhances the physical properties (stretch and tensile index) of paper from wheat straw, while dewatering properties are slightly diminished. Belongs to the glycosyl hydrolase 5 (cellulase A) family.