| Summary: | Antimicrobial proteins or peptides are universal feature of the defense systems of
virtually all forms of life, with representatives found in organisms ranging from
bacteria to plants and mammals. Antimicrobial peptides are typically relatively short,
positively charged and amphiphilic. In this experiment, soluble proteins were
extracted from three types of mushrooms which were L edodes, A. polytricha and P.
sp., but only two samples (L. edodes and A. polytricha) possessed antimicrobial
properties. Two extraction methods that were used in this experiment such as distilled
water extraction and salt solution extraction. The efficiency of these two methods was
compared by the determination of protein recovery using Bradford assay. From the
experiment, the salt solution extraction was found better due to the higher protein
recovery of 20.37% and 18.52% for sample L.e.2 and P.sp.2 respectively. In order to
analyze the antifungal and antibacterial activities of the proteins, disk diffusion assays
was applied for each sample and the MIe values were determined for each sample
with antimicrobial activities. The extracted protein of all samples were found less
effective against Gram-negative bacterium Pseudomonas aeruginose and fungus
Botrytis cinerea, but L. edodes and A. polytricha demonstrated inhibitory activity
against Gram-positive bacteria Streptococcus aureus and Bacillus cereus. The
proteins in vitro exhibited effective antibacterial activities against the both strains of
bacteria at minimum concentration of 0.5mg/ml, except sample L.edodes that
inhibited the growth of S. aureus even with concentration of 0.2Smglml. Apart from
that, the antioxidant activities of the proteins were investigated by applying DPPH
free radical-scavenging assay. There was only low potency of the antioxidant
activities showed by all the protein extracts with the highest 29.44%. The protein
extracted from the both samples was purified using DEAE-cellulose chromatography.
However, there was low protein recovery shown by the Bradford assay. The purity
and molecular mass of the extracted and purified proteins were then determined by
SDS-PAGE analysis. The purified proteins of sample L. edodes and A. polytricha
were found appear as few protein bands with range of size 18-55kDa and 15-50kDa
respectively.
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