The quantity of intracellular ChiB increased after 3 days of incubation, peaked at day 4, and then decreased gradually (Fig.  3 a).

The quantity of extracellular ChiB gradually increased with incubation time (Fig.  3 c).

There was a good correlation between chitinase activity and protein levels for both intracellular and extracellular ChiB (Fig.  3 b, d).

In the samples prepared from a chiB deletion mutant (strain B11, see Materials and methods ), only a little intracellular and almost no extracellular chitinase activity was detected even after 6 days of incubation (Fig.  3 b, d). .

At this point massive production of ChiB occurred (Fig.  3 a, c).

nidulans : First, we found that ChiB is responsible for the major chitinase activity during the autolytic phase (Fig.  3 ).

Indeed, we found high levels of the enzymatically active protein in the culture medium (Fig.  3 ), but the determination of the initiation codon revealed that ChiB lacks the hydrophobic N-terminal region upstream of M2 (Figs.  1 , 2 ), a sequence that could function as a respective secretion signal.

Comparing Figs.  3 d and 4 b, one may conclude that the autolytic process indeed starts somewhat earlier than the massive secretion of ChiB.