Inulin is emerging as an extremely rare source of sugar, it is having more 
sweetening capacity than table sugar, has beneficial effect in diabetic patient. 
Inulinases mainly produced by the microorganism and it degrades inulin into 
fructose which is a digestible form. There are more than 58 strains of 
microorganisms which are involved in the production of inulinases. The present 
report investigates about the selectivity of inulin by inulinase and its action 
to produce fructose through molecular docking. We have investigated 
exo-inulinase and endo-inulinases from Penicillium sp. TN-88(BAC16218) and 
Penicillium sp. TN-88(BAA19132), respectively with different arrangement of 
amino acids in the active site which detect the substrate. The protein sequences 
described above were processed to homology modeling by Swiss model and further 
they were docked with 1-ketose and fructose-6-phosphate as substrate by DOCK6 
software package (dock.compbio.ucsf.edu). The results of the present studies 
represented that fructose-6-phosphate ((2R,3R,4S) fructose-6-phosphate) was 
having better interaction with exo-inulinase showing grid score of -40.288094 
and the conserved amino acid Asp-22, Asp 128, Asp 179 and Ser 84 of 
exo-inulinase are involved in the bonding. In addition to this it was also seen 
that 1-ketose ((3S,4R)-ketose 1-phosphate) did not shown any interaction with 
the conserved part of the endo-inulinase.