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Characterization of a Phenol Oxidase from Cryptococcus neoformans var. neoformans
Author(s) -
Ikeda Reiko,
Shinoda Takako,
Morita Takashi,
Jacobson Eric S.
Publication year - 1993
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.1993.tb01702.x
Subject(s) - cryptococcus neoformans , isoelectric point , biology , chromatography , oxidase test , biochemistry , isoelectric focusing , size exclusion chromatography , enzyme , ion chromatography , gel electrophoresis , microbiology and biotechnology , chemistry
In Cryptococcus neoformans , enzymic oxidation of various catechols leads to melanin, a proposed virulence factor. A phenol oxidase enzyme of Cryptococcus neoformans var. neoformans produced at 25 C has been purified from an ultracentrifugal supernatant of an extract of broken cells. Hydrophobic interaction chromatography followed by anion‐exchange column chromatography allowed purification of the phenol oxidase. The molecular weight of the enzyme estimated by gel filtration was about 80,000 and a dimeric species (Mw = 160,000) was suggested. The isoelectric point of the protein was approximately 4.1. An NH 2 ‐terminal 31 amino acid sequence was determined using phenol oxidase electroblotted onto a PVDF membrane after nondenaturing gel electrophoresis. Upon searching the Peptide Institute (Osaka) data base, no proteins with high degrees of homology were found.