in my result the analysis of hydrolase products via HPLC revealed that the main products for β-glucanase once hydrolysed the laminarin as substrate, were glucose, laminaribiose and laminaritetraose, while exo acting enzyme could hydrolyse the β-glucan from non reducing end and the final product is mono or dimer as sole end product.
how can explain my result , is there any possibility this enzyme could act as both endo and exo enzyme?
The best method to evaluate the endo or exo mechanism of a polysaccharide degrading enzyme is the rheology of the substrate solution. During cleavage of polysaccharide by an exoenzyme the decraesing of viscosity is linear whereas when an endoenzyme is acting the viscosity decreases a lot in a first time of kinetics.
Generally, exoenzymes led to obtaining of a sole product (mono or disaccharide). So if in the first time of kinetic you can detect only one species of mono- or dimeric product , this enzyme cleave the glycosidic bonds with an exomechanism.
Endoglucanase breaks the polysaccharide to give new chains where as exoglucanase breaks these chains to give dimers, tetramers. Since you are getting dimers, tetramers it must be exo type. Further there are two types of exo, I and II.
Laminarin is beta 1-3 bond where as cellulose have beta 1-4 bonds. Most study on exo and endo enzymes is in reference to enzymes acting on cellulose.
As Philippe mentioned rheology study can give you better answers along with the data on sugar analysis. If viscocity decreases fast with no dimers tetramers then its endo but if viscocity is not reduced much and you still see dimers, tetramers then its exo.
Thank you very much Philippe and shrikant for useful suggestion, it helped me a lots.
My suggestion please perform the TLC(thin layer chromatography). Please find these link for further....
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