Modification of chitin as substrates for chitinase

Abstract

Enzymes are able to bind to their substrates specifically at the active site. The proximity and orientation of the substrates strongly increase the likelihood that productive E–S complexes will arise. Treated chitin (powder or flake) is more efficient than crystalline chitin. This is because the latter is less active due to its insolubility. The structure of treated chitin is opened; this facilitates its interaction with the enzyme. The purpose of this research was to create a kind of modified chitin and study the characterization of the different types of chitin including functional groups by IR spectrophotometer, pore size, surface area and crystallinity by X-Ray diffraction. Chitin from shrimp shell was modified into colloidal, bead, amorphous and superfine chitin. The results of the IR spectra of colloidal and bead chitin showed a similar pattern with chitin powder; they peaked at 3447 and 3113 cm^-1 (OH and NH₂ groups), 1645 cm^-1 (amide groups N-H) and 1071 cm^-1 (group C-O). Superfine and amorphous chitin had similar absorbance with powder chitin but appeared to peak in the fingerprint region. Characterization of physical properties based on the pore size and surface area of powder, colloidal, superfine, amorphous and bead chitin changed the pore radius of each type of chitin due to the treatment of swelling. Crystallinity showed that specific diffractogram pattern in the three main peaks 2q was 9.5, 19.5 and 26 with varying intensity. Chitinase activity assay using modified types of chitin substrate had higher values than chitin powder. The highest activity was in amorphous chitin with values of 1.858 U/mL. This is because it has chitin chain and the rearrangement of its structure was more open, facilitating its interaction with enzyme.

Keywords: Chitin modified, chitinase, substrate.

Abbreviation: SDS, Sodium dodecyl sulfate; Ct, chitin powder; Cc, colloidal chitin; Sf, superfine; Cb, bead; Ca, amorphous.