Literature summary for 3.4.22.B49 extracted from

Lowther, J.; Robinson, M.W.; Donnelly, S.M.; Xu, W.; Stack, C.M.; Matthews, J.M.; Dalton, J.P.
The importance of pH in regulating the function of the Fasciola hepatica cathepsin L1 cysteine protease (2009), PLoS Negl. Trop. Dis., 3, e369.

Search for more literature for 3.4.22.B49

Activating Compound

Activating Compound	Comment	Organism	Structure
dithiothreitol	activitation, with maximum activity around 0.1-1 mM	Fasciola hepatica
DTT	the action of FheCL1 is enhanced by glutathione, the major reducing agent found in red blood cells. In the presence of DTT, GSH and L-cysteine FheCL1 exhibited similar activation curves with maximal enzyme activity observed in the presence of each reducing agent at a concentration of 0.1 to 1.0 mM	Fasciola hepatica
glutathione	the action of FheCL1 is enhanced by glutathione, the major reducing agent found in red blood cells. In the presence of DTT, GSH and L-cysteine FheCL1 exhibited similar activation curves with maximal enzyme activity observed in the presence of each reducing agent at a concentration of 0.1 to 1.0 mM	Fasciola hepatica
glutathione	activitation, with maximum activity around 0.1-1 mM	Fasciola hepatica
L-Cys	the action of FheCL1 is enhanced by glutathione, the major reducing agent found in red blood cells. In the presence of DTT, GSH and L-cysteine FheCL1 exhibited similar activation curves with maximal enzyme activity observed in the presence of each reducing agent at a concentration of 0.1 to 1.0 mM	Fasciola hepatica
L-cysteine	activitation, with maximum activity around 0.1-1 mM	Fasciola hepatica

Cloned(Commentary)

Cloned (Comment)	Organism
expression in Pichia pastoris	Fasciola hepatica

Protein Variants

Protein Variants	Comment	Organism
C25G	inactive zymogen since the active site Cys is replaced by a Gly	Fasciola hepatica

Molecular Weight [Da]

Molecular Weight [Da]	Molecular Weight Maximum [Da]	Comment	Organism
25000	-	x * 25000, mature enzyme, x * 38000, zymogen, SDS-PAGE	Fasciola hepatica
38000	-	x * 25000, mature enzyme, x * 38000, zymogen, SDS-PAGE	Fasciola hepatica

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
Hemoglobin + H2O	Fasciola hepatica	Fasciola hepatica secretes cathepsin L cysteine proteases to invade its host, migrate through tissues and digest hemoglobin, its main source of amino acids. FheCL1 can degrade hemoglobin to small peptides, predominantly of 414 residues, but cannot release free amino acids. It is suggested that hemoglobin degradation is not completed in the gut lumen but the resulting peptides are absorbed by the gut epithelial cells for further processing by intracellular di- and amino-peptidases to free amino acids that are distributed through the parasite tissue for protein anabolism. The action of FheCL1 is enhanced by glutathione, the major reducing agent found in red blood cells	?	-	?
Hemoglobin + H2O	Fasciola hepatica	enzyme does not cleave its natural substrate hemoglobin in the pH range pH 5.5 and pH 7.0. Digestion occurs only at pH 4.5, which coincides with pH-induced dissociation of the hemoglobin tetramer	?	degradation to small peptides of 4-14 residues, no release of free amino acids	?

Organism

Organism	UniProt	Comment	Textmining
Fasciola hepatica	-	-	-

Posttranslational Modification

Posttranslational Modification	Comment	Organism
proteolytic modification	slightly acidic pH of the parasite gut facilitates the auto-catalytic activation of FheCL1 from its inactive proFheCL1 zymogen. This process is about 40fold faster at pH 4.5 than at pH 7.0. The zymogen proFheCL1 (38000 Da) is auto-catalytically processed at pH 4.5 by intermolecular cleavage and removal of the prosegment to release a fully mature and active enzyme (25000 Da)	Fasciola hepatica
proteolytic modification	auto-activation of the inactive zymogen proCL1 in the slightly acidic gut. The autoactivation process is 40fold faster at pH 4.5 than at pH 7.0. Molecular weight of zymogen is 38 kDa, of mature form 25 kDA, respectively	Fasciola hepatica

Purification (Commentary)

Purification (Comment)	Organism
-	Fasciola hepatica

Source Tissue

Source Tissue	Comment	Organism	Textmining
gut	the slightly acidic pH value of gut facilitates auto-activation of the inactive zymogen proCL1	Fasciola hepatica	-

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
benzyloxycarbonyl-L-Phe-L-Arg-4-methylcoumarinyl-7-amide + H2O	FheCL1	Fasciola hepatica	benzyloxycarbonyl-L-Phe-L-Arg + 7-amino-4-methylcoumarin	-	?
benzyloxycarbonyl-Phe-Arg-7-amido-4-methylcoumarin + H2O	-	Fasciola hepatica	benzyloxycarbonyl-Phe-Arg + 7-amino-4-methylcoumarin	-	?
Hemoglobin + H2O	Fasciola hepatica secretes cathepsin L cysteine proteases to invade its host, migrate through tissues and digest hemoglobin, its main source of amino acids. FheCL1 can degrade hemoglobin to small peptides, predominantly of 414 residues, but cannot release free amino acids. It is suggested that hemoglobin degradation is not completed in the gut lumen but the resulting peptides are absorbed by the gut epithelial cells for further processing by intracellular di- and amino-peptidases to free amino acids that are distributed through the parasite tissue for protein anabolism. The action of FheCL1 is enhanced by glutathione, the major reducing agent found in red blood cells	Fasciola hepatica	?	-	?
Hemoglobin + H2O	FheCL1 can degrade hemoglobin to small peptides, predominantly of 414 residues, but cannot release free amino acids. FheCL1 can not cleave its natural substrate hemoglobin in the pH range pH 5.5 and pH 7.0. Digestion occurs only at or below pH 4.5, which coincides with pH-induced dissociation of the hemoglobin tetramer. The acidic pH of the parasite relaxes the hemoglobin structure, making it susceptible to proteolysis by FheCL1. The P1 position could be occupied by many amino acids but most preferentially Leu. FheCL1 preferentially cleaves bonds where the P2 position is occupied with hydrophobic residues (in order of decreasing efficiency: Leu, Val, Ala, Phe) and is observed for the digestion of both hemoglobin-alpha and hemoglobin-beta	Fasciola hepatica	?	-	?
Hemoglobin + H2O	enzyme does not cleave its natural substrate hemoglobin in the pH range pH 5.5 and pH 7.0. Digestion occurs only at pH 4.5, which coincides with pH-induced dissociation of the hemoglobin tetramer	Fasciola hepatica	?	degradation to small peptides of 4-14 residues, no release of free amino acids	?
additional information	enzyme preferentially cleaves bonds where the P2 position is occupied with hydrophobic residues, this preference follows the order Leu>Val>Ala>Phe, and is observed for the digestion of both hemoglobin-alpha and hemoglobin-beta	Fasciola hepatica	?	-	?
ovalbumin + H2O	-	Fasciola hepatica	?	-	?
ovalbumin + H2O	FheCL1 can degrade ovalbumin from pH 3.5 to pH 8.0	Fasciola hepatica	?	-	?

Subunits

Subunits	Comment	Organism
?	x * 25000, mature enzyme, x * 38000, zymogen, SDS-PAGE	Fasciola hepatica

Synonyms

Synonyms	Comment	Organism
cathepsin L1	-	Fasciola hepatica
FheCL1	-	Fasciola hepatica

Temperature Stability [°C]

Temperature Stability Minimum [°C]	Temperature Stability Maximum [°C]	Comment	Organism
37	-	retains 45% of activity when incubated at 37°C and pH 4.5 for 10 days	Fasciola hepatica

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
6.2	-	-	Fasciola hepatica
6.2	-	maximal activity between pH 5.57.0 with a peak at pH 6.2, substrate: benzyloxycarbonyl-L-Phe-L-Arg-4-methylcoumarinyl-7-amide	Fasciola hepatica

pH Range

pH Minimum	pH Maximum	Comment	Organism
3	9	the enzyme has the capacity to cleave substrates over a wide pH range	Fasciola hepatica
5.5	7	substrate ovalbumin	Fasciola hepatica

pH Stability

pH Stability	pH Stability Maximum	Comment	Organism
2.5	-	37°C, enzyme activity is not completely lost until day three	Fasciola hepatica
3	-	37°C, 10 days, 1 mM DTT, 95% loss of activity, mature FheCL1	Fasciola hepatica
4.5	-	37°C, 10 days, 1 mM DTT, 55% loss of activity, mature FheCL1	Fasciola hepatica
4.5	-	retains 45% of activity when incubated at 37°C and pH 4.5 for 10 days	Fasciola hepatica
4.5	7.5	zymogen is stable within this range	Fasciola hepatica

Use of this online version of BRENDA is free under the CC BY 4.0 license. See terms of use for full details.

Release 2023.1 (January 2023)