Reference "Isolation and partial characterization of two antifungal proteins from barley"

Reference ID

8745

Title

Isolation and partial characterization of two antifungal proteins from barley

Source

Biochimica et biophysica acta, 1986, vol. 880, pp. 161-170

Authors (2)

Roberts-W-K

Selitrennikoff-C-P

Abstract

We have developed a simple assay for detecting antifungal compounds utilizing
impregnated paper discs on agar to inhibit mycelial spread of an indicator
organism, Trichoderma reesei. Using this assay we have isolated and purified to
apparent homogeneity two antifungal proteins from dehusked barley grain. Both
proteins are present at high concentrations: over 10 mg of each protein can be
isolated per 100 g of grain. The first protein has a molecular weight of 30 000
and is identical to the 30 kDa ribosome-inactivating protein previously isolated
from barley. This protein very effectively inactivates fungal ribosomes and this
may explain its antifungal activity and biological role. The second antifungal
protein has a molecular weight of 28 000 and is 20-fold more potent than the 30
kDa protein in inhibiting growth of Trichoderma. In addition to Trichoderma, the
28 kDa protein also efficiently inhibits growth of Phycomyces blakesleeanus,
Alternaria alternaria and a protoplast-forming mutant of Neurospora crassa. The
28 kDa protein does not inactivate fungal ribosomes and we are currently
investigating other possible enzymatic activities of this protein.