Specific cleavage of Pseudomonas cytochrome-c peroxidase by elastase from Pseudomonas aeruginosa.
The occasional cleavage of the Pseudomonas cytochrome-c peroxidase (ferrocytochrome-c:hydrogen-peroxide oxidoreductase, EC 1.11.1.5) molecule into two well-defined fragments during the preparation of the enzyme is shown to be identical to that caused by elastase isolated from the culture solution of Pseudomonas aeruginosa. A cyanogen bromide fragmentation of proteolytically cleaved and of intact enzyme shows the cleaved peptide bond to be situated in cyanogen bromide fragment II. The amino-acid sequence of this fragment was established by sequencing peptides obtained with trypsin, thermolysin, chymotrypsin and o-iodosobenzoate. It is concluded from the sequence homology that the polypeptide chain of Pseudomonas peroxidase is wrapped around the high-potential heme in a similar manner as in high-potential cytochromes c in general. The specific proteolytic cleavage occurs at a Ser-Val (Leu-Pro) region which is assumed to be the site of attachment between enzyme and membrane. The cleavage of the Ser-Val bond renders the peroxidase molecule enzymatically inactive by impeding the conformational changes essential for the function of the native enzyme.
Rönnberg
M
M
Department of Biochemistry, University of Helsinki, Finland.
D000595:Amino Acid Sequence; D003488:Cyanogen Bromide / Q000494:pharmacology; D003578:Cytochrome-c Peroxidase / Q000378:metabolism*; D008969:Molecular Sequence Data; D010196:Pancreatic Elastase / Q000378:metabolism*; D010449:Peptide Mapping; D010544:Peroxidases / Q000378:metabolism*; D011549:Pseudomonas / Q000201:enzymology*; D011550:Pseudomonas aeruginosa / Q000201:enzymology*
D010544:Peroxidases; D003578:Cytochrome-c Peroxidase; D010196:Pancreatic Elastase; D003488:Cyanogen Bromide