The effects of N-substitution of chitosan and the physical form of the products on the rate of hydrolysis by chitinase from Streptomyces griseus.

N-Formyl, N-chloroacetyl, N-glycyl, N-isobutyryl, and N-pentanoyl derivatives of chitosan have been prepared. N-Acetylchitosan was the derivative most susceptible to chitinase from Streptomyces griseus and lysozyme from chicken egg-white, but with respect to R in the RCOHN group were CH3 > CH3CH2 > H > CH3CH2CH2 > (CH3)2CH > NH2CH2 > CICH2. Neither enzyme hydrolysed chitosan or its N-methylene. N-benzylidene, N-benzoyl, N-nicotinyl, and N-fatty acyl (C5-C18) derivatives, and lysozyme did not hydrolyse N-butyrychitosan. N-Acetylhexanoyl-chitosans, which had d.s. ratios of approximately 0.7: approximately 0.3 and approximately 0.3: approximately 0.7, were hydrolysed at approximately 0.75 and approximately 0.004 of the rate of N-acetylchitosan (powder) by chitinase. O-Acylation of N-acylchitosans caused a decrease in the rates of hydrolysis by chitinase. N-Acetylchitosan gels were hydrolysed at 8-13 times the rate for crab-shell chitin. These results indicate that not only N- and O-substituents but also the physical form of the substrates influence the rates of hydrolysis by these enzymes.