Abstract
The fungal disease Fusarium head blight occurs on wheat (Triticum spp.)
and barley (Hordeum vulgare L.) and is one of the worldwide problems of
agriculture. It can be caused by various Fusarium species. We are
characterizing the proteinases of F. culmorum to investigate how they may
help the fungus to attack the grain. A trypsin-like proteinase has been
purified from a gluten-containing culture medium of F. culmorum. The enzyme
was maximally active at about pH 9 and 45 C, but was not stable under those
conditions. It was stabilized by calcium ions and by the presence of other
proteins. The proteinase was most stable at pH 6-7 at ambient temperatures,
but was quickly inactivated at 50 C. It was strongly inhibited by p-amidino
phenylmethylsulfonyl fluoride (p-APMSF), and soybean trypsin and Bowman-Birk
inhibitors, and it preferentially hydrolyzed the peptide bonds of the
protein substrate -purothionin on the C-terminal side of Arg (mainly) and Lys
residues. These characteristics show that it is a trypsin-like proteinase.
In addition, its N-terminal amino acid sequence was 88% identical to that of
the F. oxysporum trypsin-like enzyme. The proteinase hydrolyzed the D
hordein and some of the C hordeins (the barley storage proteins). This
enzyme, and a subtilisin-like proteinase that we recently purified from the
same organism, possibly play roles in helping the fungus to colonize grains.
Original language | English |
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Pages (from-to) | 3849-3855 |
Journal | Journal of Agricultural and Food Chemistry |
Volume | 50 |
Issue number | 13 |
DOIs | |
Publication status | Published - 2002 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Fusarium
- cereals
- barley (Hordeum vulgare L.)
- trypsin
- proteinase