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Digestion of single crystals of mannanâI by an endoâmannanase from Trichoderma reesei
- Sabini, Elisabetta, Wilson, Keith S., Siikaâaho, Matti, Boisset, Claire, Chanzy, Henri
- European journal of biochemistry 2000 v.267 no.8 pp. 2340-2344
- Trichoderma reesei, crystals, digestion, transmission electron microscopy
- The enzymatic degradation of single crystals of mannanâI with the catalytic core domain of a Î²âmannanase (EC 188.8.131.52 or Man5A) from Trichodermaâreesei was investigated by transmission electron microscopy and electron diffraction. The enzyme attack took place at the edge of the crystals and progressed towards their centres. Quite remarkably the crystalline integrity of the crystals was preserved almost to the end of the digestion process. This behaviour is consistent with an endoâmechanism, where the enzyme interacts with the accessible mannan chains located at the crystal periphery and cleaves one mannan molecule at a time. The endo mode of digestion of the crystals was confirmed by an analysis of the soluble degradation products.