Solid-state CP/MASS 13C-NMR spectroscopy: a sensitive method to monitor enzymatic hydrolysis of chitin

The time-course hydrolysis of colloidal chitin by the chitinase complex isolated from Myrothecium verrucaria was monitored using solution and solid-state 13C-NMR spectroscopy. The solution NMR studies showed the presence of N-acetylglucosamine (GlcNAc) as the sole product of hydrolysis. Solid-state 13C CP/MASS studies, on the other hand, indicated the presence of high molecular weight oligomers as well as GlcNAc. The linewidth of the C1 carbon of the oligomers obtained after hydrolysis is found to be less than that of the unhydrolyzed sample. The linewidths calculated from the spin-spin relaxation times (T2) of colloidal chitin and its products of hydrolysis were in the restricted range of 40-50 Hz, compared with the observed linewidths of 143-123 Hz. Peak area measurement on monomer to polymer/oligomer indicated an initial slow formation of the monomer, GlcNAc. From the NMR data, the involvement of endo-enzymes in the initial phase of hydrolysis is suggested.