Family I67
Summary for family I67
| Name | Inhibitor family I67 (bromein family) |
|---|
| Family type peptidase | I67.001 - bromein (Ananas comosus), MEROPS Accession MER0018125 (inhibitor unit: 20-53) |
| Content of family | Inhibitor family I67 contains inhibitors of cysteine endopeptidases. |
| History |
Identifier created: MEROPS 7.1 (26 July 2005)
Bromein is an inhibitor of stem bromelain (C01.005) that is derived from the same source, pineapple stem (Reddy et al., 1975). Several isoforms exist, and the precursor protein contains three homologous inhibitor domains. Stem bromelain has been shown to process the linker propeptide between the light and heavy chains of one of these inhibitory domains (Sawano et al., 2005). |
| Peptidases inhibited | Stem bromelain is the target peptidase, but weak inhibition of trypsin (S01.151) and chymotrypsin (S01.001) has also been shown (Sawano et al., 2005). |
| Molecular structure | Bromein is a disulfide-bonded heterodimer consisting of an eleven-residue light chain and a 41-residue heavy chain. The tertiary structure has been solved by nuclear magnetic resonance spectroscopy and show that the protein consists of two domains, each of which contains a three-stranded antiparallel beta-sheet. The fold is unexpectedly similar to that of members of family I12, which contains inhibitors of serine-type peptidases, and not cystatins (I25) (Hatano et al., 1996). Consequently, family I67 is included in clan IF. |
| Clan | IF |
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Distribution of family
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Bacteria |
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Archaea |
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Protozoa |
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Fungi |
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Plants |
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Animals |
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Viruses |
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| Inhibitors and Homologues |
MEROPS ID |
Structure |
| bromein | I67.001 | Yes |
| Family I67 unassigned peptidases | unassigned | - |
