2Bach Institute of Biochemistry, Russian Academy of Sciences, 119071 Moscow, Russia; fax: +7 (495) 954-2732; E-mail: email@example.com
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Received November 25, 2014; Revision received December 30, 2014
The genes of endoglucanases EG2 (36.2 kDa) Penicillium verruculosum and LAM (30.8 kDa) Myceliophthora thermophila were cloned in P. verruculosum recombinant strain. New enzyme preparations with highly stable activity against β-glucan and laminarin were obtained and investigated, homogeneous enzymes EG2 (EC 184.108.40.206) and LAM (EC 220.127.116.11) being purified and characterized. For β-glucan, the EG2 Km value was found to be 10 times higher than that for LAM; however, EG2 demonstrated greater processivity due to its higher kcat. The pH and temperature optima of EG2 and LAM activity against barley β-glucan overlapped and were 4.3-4.9 and 61-67°C, respectively, and EG2 appeared to be more stable than LAM. Oligosaccharides with degree of polymerization 2-10 were formed by hydrolysis of β-glucan and laminarin by the studied enzymes. The recombinant enzyme preparations were faster and more effective in decreasing the reduced viscosity of wholegrain barley extract than some commercial enzyme preparations. Thus, the new enzyme preparations seem to be rather perspective as feed additives for degradation of non-starch polysaccharides in grain animal feed.
KEY WORDS: endoglucanase, β-glucan, β-glucan endodepolymerases, enzyme preparations, Penicillium verruculosum, Myceliophthora thermophila