R. Ikeda et al., CHARACTERIZATION OF A PHENOL OXIDASE FROM CRYPTOCOCCUS-NEOFORMANS VARNEOFORMANS, Microbiology and immunology, 37(10), 1993, pp. 759-764
In Cryptococcus neoformans, enzymic oxidation of various catechols lea
ds to melanin, a proposed virulence factor. A phenol oxidase enzyme of
Cryptococcus neoformans var. neoformans produced at 25 C has been pur
ified from an ultracentrifugal supernatant of an extract of broken cel
ls. 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 8
0,000 and a dimeric species (Mw = 160,000) was suggested. The isoelect
ric point of the protein was approximately 4.1. An NH2-terminal 31 ami
no acid sequence was determined using phenol oxidase electroblotted on
to a PVDF membrane after nondenaturing gel electrophoresis. Upon searc
hing the Peptide Institute (Osaka) data base, no proteins with high de
grees of homology were found.