Summary for peptidase C01.092: cathepsin L1 (arthropod-type)

Summary Gene structure Alignment Tree Sequences Sequence features Distribution Literature Substrates Inhibitors

 

Names
MEROPS Namecathepsin L1 (arthropod-type)
Other namesBoophilus microplus cathepsin-L1 (BmCL1), cathepsin L-like endopeptidase (insect), Cp1 g.p. (Drosophila melanogaster), cysteine proteinase-1 (Drosophila melanogaster), DcCathL (Delia coarctata), fibroinase (Bombyx mori), HlCPL-A peptidase (Haemaphysalis longicornis), Mername-AA198 peptidase, Mername-AA288 peptidase, ScathL (Sarcophaga peregrina), vitellin-degrading cysteine endopeptidase (Boophilus) microplus), VTDCE
Name and HistoryThe peptidase was first purified and characterized from silkworm eggs (Kageyama & Takahashi, 1990).
Domain architecture
MEROPS Classification
Classification Clan CA >> Subclan (none) >> Family C1 >> Subfamily A >> C01.092
Holotypecathepsin L1 (arthropod-type) (Bombyx mori) (peptidase unit: 123-341), MERNUM MER0002331
History Identifier created: MEROPS 3.02 (25 June 1998)
Activity
Catalytic typeCysteine
NC-IUBMBNot yet included in IUBMB recommendations.
PreparationThe peptidase has been purified using a six-step process that utilises anion-exchange chromatography (Kageyama & Takahashi, 1990). A recombinant protein has been efficiently expressed in E. coli. However, the product was insoluble and required solubilization and renaturation (Yamamoto et al., 1999).
BiotechnologyTarget for pest control.
SpecificityThe specificity is similar to that of cathepsin L. The S3 binding site was found to be almost always occupied by hydrophobic residues such as Phe, Val and Leu (Kageyama & Takahashi, 1990).
pH optimumThe peptidase is maximally active between pH 3 and 3.5 (Kageyama & Takahashi, 1990).
Substrate commentsThe peptidase degrades bovine haemoglobin, vitellin and vitellogenin (Kageyama & Takahashi, 1990).
Inhibitor commentsEDTA and phosphoramidon enhance activity (Kageyama & Takahashi, 1990).
StructureUndenatured peptidase from silkworm has a mass of upto 380 kDa, which on denaturation reduces to 47 kDa, indicating the peptidase assembles into a complex of eight identical subunits (Kageyama & Takahashi, 1990). The predicted mass of a mature monomer is 24.5 kDa, and SDS-PAGE of recombinant mature protein gives a mass of 39 kDa, suggesting it is post-translationally modified. Because the active enzyme does not react with periodic acid-Schiffs reagent, the difference in mass is not a result of glycosylation (Yamamoto et al., 1994).
PhysiologyInsect nutrition.
Biological aspectsIn B. mori the peptidase is produced as a 328 amino acid proenzyme. A propeptide of 104 amino acid residues is removed to give a 224 amino acid active enzyme (Yamamoto et al., 1994). The inactive proenzyme accumulates in yolk granules (considered homologous organelles to lysosomes) within unfertilised eggs, and is activated when development starts (Takahashi, 1993). The proenzyme and mature forms can both be found in fat bodies and hemocytes, whereas in ovaries and hemolymph, primarily proenzyme has been found. In the testes, most is in mature form (Yamamoto et al., 1994). In the flesh fly, it is secreted by imaginal discs and larval brains (Homma & Natori, 1996;Fujii-Taira et al., 2000). It is present in alimentary organs of insects (Matsumoto et al., 1995:Matsumoto et al., 1997).
KnockoutNull mutant studies in Drosophila produced infertile females, sometimes infertile males, with both sexes showed wing and pigmentation defects (Gray et al., 1998).
Distinguishing featuresFor mammalian lysosomal peptidases the masses range between 20-35kDa, so compared to these, the large mass and polymeric structure of this peptidase is unusual.(Kageyama & Takahashi, 1990).
Contributing authorsKoichi J. Homma, Faculty of Pharmaceutical Sciences, Teikyo University, 2-11-1 Kaga, Itabashi-ku, Tokyo, 173-8605, Japan
Other databases PANTHERhttp://www.pantherdb.org/panther/familyList.do?searchType=basic&fieldName=all&listType=6&fieldValue=PTHR12411:SF414
Cleavage site specificity Explanations of how to interpret the following cleavage site sequence logo and specificity matrix can be found here.
Cleavage pattern-/l/-/-Scissile bond-/-/-/- (based on 12 cleavages)
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Specificity matrix
 
Amino acid P4 P3 P2 P1 P1' P2' P3' P4'
Gly 2 2 0 1 3 0 1 2
Pro 0 0 0 0 0 1 1 0
Ala 1 1 1 0 1 0 0 1
Val 1 0 3 0 1 1 1 0
Leu 0 3 2 2 1 2 1 2
Ile 0 0 0 0 0 0 0 0
Met 0 0 0 0 0 0 0 0
Phe 0 2 3 1 1 2 1 0
Tyr 1 0 1 2 2 0 2 1
Trp 0 0 0 0 0 0 0 0
Ser 0 0 0 0 0 1 0 0
Thr 0 0 0 0 1 1 0 1
Cys 0 0 0 0 0 0 0 1
Asn 0 0 0 1 0 0 0 0
Gln 1 0 0 0 1 0 0 0
Asp 0 0 0 0 0 0 0 0
Glu 1 2 1 1 0 1 0 1
Lys 0 0 0 0 0 0 1 1
Arg 1 0 1 2 0 0 1 0
His 1 1 0 0 0 1 1 0