title: Purification and characterisation of a novel 34,000-Mr cell-associated proteinase from the dermatophyte Trichophyton rubrum.
abstract: A novel cell-associated proteinase was purified to homogeneity from cytoplasmic antigen preparations of Trichophyton rubrum by sequential isoelectric focusing and gel filtration chromatography. The enzyme exhibited relative molecular masses of 34,000-Mr (non-reduced sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE)), 15,000-Mr (reduced SDS-PAGE) and 37,000-Mr (substrate SDS-PAGE). It had a pH optimum of 7.5 and a pI of 4.5. The proteinase exhibited broad substrate specificity and it was strongly inhibited by the serine proteinase inhibitors phenylmethylsulfonyl fluoride and chymostatin. The N-terminal amino acid sequence of the 34,000-Mr proteinase shared 50% homology with the deduced amino acid sequence of a Coccidioides immitis wall-associated chymotrypsin-type serine proteinase. This is the first cell-associated proteinase to be purified and characterised from T. rubrum and it would appear to be related to the chymotrypsin-type serine proteinases, a class of enzymes that have rarely been isolated from fungi. The function of the proteinase remains speculative although it may play a role in the development and subsequent proliferation of the fungus in vivo.
authors.affiliation: Dermatology Unit, Clinical Sciences Laboratory, Guys Hospital, London, UK.
authors.forename: I
authors.initials: I
authors.lastname: Lambkin
authors.forename: A J
authors.initials: AJ
authors.lastname: Hamilton
authors.forename: R J
authors.initials: RJ
authors.lastname: Hay
mesh_terms: D000595:Amino Acid Sequence; D002412:Cations; D005656:Fungal Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000302:isolation & purification*; D007526:Isoelectric Point; D008670:Metals / Q000494:pharmacology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000302:isolation & purification*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D013379:Substrate Specificity; D014249:Trichophyton / Q000201:enzymology*
chemical_list: D002412:Cations; D005656:Fungal Proteins; D008670:Metals; D015842:Serine Proteinase Inhibitors; D012697:Serine Endopeptidases