The identification and biochemical properties of the catalytic specificity of a serine peptidase secreted by Aspergillus fumigatus Fresenius.
Aspergillus fumigatus is a saprophytic fungus as well as a so-called opportunist pathogen. Its biochemical potential and enzyme production justify intensive studies about biomolecules secreted by this microorganism. We describe the alkaline serine peptidase production, with optimum activity at 50°C and a pH of 7.5 and a reduction in proteolytic activity in the presence of the Al(+3) ions. When using intramolecularly quenched fluorogenic substrates, the highest catalytic efficiency was observed with the amino acid leucine on subsite S'(3) (60,000 mM(-1)s(-1)) and preference to non-polar amino acids on subsite S(3). In general, however, the peptidase shows non-specificity on other subsites studied. According to the biochemical characteristics, this peptidase may be an important biocatalyst for the hydrolysis of an enormous variety of proteins and can constitute an essential molecule for the saprophytic lifestyle or invasive action of the opportunistic pathogen. The peptidase described herein exhibits an estimated molecular mass of 33 kDa. Mass spectrometry analysis identified the sequence GAPWGLGSISHK displaying similarities to that of serine peptidase from Aspergillus fumigatus. These data may lead to a greater understanding of the advantageous biochemical potential, biotechnological interest, and trends of this fungus in spite of being an opportunist pathogen.
Ronivaldo Rodrigues
RR
da Silva
Renato Cesar
RC
Caetano
Debora Nona
DN
Okamoto
Lilian Caroline Goncalves
LC
de Oliveira
Thiago Carlos
TC
Bertolin
Maria Aparecida
MA
Juliano
Luiz
L
Juliano
Arthur H C
AH
de Oliveira
Jose C
JC
Rosae
Av. do Cafe, s/nº Campus Universitario da USP CEP 14040-903 Ribeirao Preto/Sao Paulo/Brazil. hamilton@fcfrp.usp.br.
Hamilton
H
Cabral
D000595:Amino Acid Sequence; D001232:Aspergillus fumigatus / Q000201:enzymology*; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors; D013696:Temperature
D015842:Serine Proteinase Inhibitors; D012697:Serine Endopeptidases