Allosamidin inhibits the fragmentation of Acremonium chrysogenum but does not influence the cephalosporin-C production of the fungus.

The pseudotrisaccharide allosamidin, a potent inhibitor of chitinases, retarded the fragmentation of hyphae but did not affect the fungal growth and cephalosporin-C production in Acremonium chrysogenum. In vitro inhibition of A. chrysogenum cell-bound chitinase(s) by allosamidin revealed that about 47% of the soluble intracellular chitinase activity was resistant to the inhibitory effect of allosamidin. On the other hand, about 76% of the total chitinase activity localised in both the soluble and insoluble enzyme fractions was effectively inhibited by allosamidin. All the chitinase activities were measured using a new procedure based on purified A. chrysogenum chitin as substrate.