Proteases from Entamoeba spp. and Pathogenic Free-Living Amoebae as Virulence Factors

Table 3

Enzymes from free-living amoebae^a that degrade host proteins and their implication in virulence.

Pathogen	Tissue or protein	Purified	Name	Mr (kDa)	Catalytic type	Localization	Reference
Acanthamoeba spp.	Elastin	No		70–130	SP	Secreted	[41]
	Collagen, fibronectin, and laminin	Yes		12	SP	Secreted	[42]
	Corneal stroma (ex vivo), Collagen I and IV	Yes	MIP-133	133	SP	Secreted	[43]
Acanthamoeba castellanii	Corneal stroma (ex vivo), Collagen	Yes	MIP-133	133	SP	Secreted	[44]
	Collagen I and III; Elastin	No		130	SP	Secreted	[45]
	Collagen I and III	No		150	MMP	Secreted	[45]
	Collagen I and IV; Fibronectin, hemoglobin, albumin, IgA, and IgG	Yes		33	SP	Secreted	[46]
	Gelatin	No		178, 144, 123, 110, 78, 75, 72, 34, 30	SP	Crude extracts	[47]
	Gelatin	No		188, 157, 53, 34	SP	Conditioned medium	[47]
Acanthamoeba polyphaga	Gelatin	No		144, 105, 78, 72, 45, 40, 34	SP	Crude extracts	[47]
	Gelatin	No		72, 62, 50, 34	SP	Conditioned medium	[47]
Acanthamoeba healyi	Collagen I and IV; Fibronectin, hemoglobin, albumin, IgA, and IgG	Yes		33	SP	Secreted	[46]
Acanthamoeba lugdunensis	Collagen I and IV; Fibronectin, hemoglobin, albumin, IgA, and IgG	Yes		33	SP	Secreted	[46]
Naegleria fowleri	Collagen I and, elastin	Yes		30	CP	Secreted and cytoplasmic	[48]
	Bovine mucin	No		37	CP	Crude extracts	[49]
	Gelatin	No		130, 100, 73, 62	CP	Crude extracts	[50]
	Gelatin	No		310, 178, 164, 147	CP	Conditioned medium	[50]
Balamuthia mandrillaris	Collagen I and III, elastin, and plasminogen	No		40–50	MMP	Crude extracts	[51]
	Collagen I and III, elastin, and plasminogen	No		73; 40–50	MMP	Conditioned medium	[51]

^aAll results have been performed in in vitro assays. MIP: mannose induced protease; SP: serine protease; CP: cysteine protease; MMP: matrix metalloprotease.