Characterization of Aspartic Proteinase Inhibitors from Potato at the Gene, cDNA and Protein Levels

Abstract

Cloning and characterization of three cDNAs and one gene coding for the aspartic proteinase inhibitor homologues, detection of four protein isoforms and analysis of the gene copy number indicate that in potato aspartic proteinase inhibitors are encoded by a multigene family.

Inhibition of cysteine and aspartyl proteinases in the alfalfa weevil midgut with biochemical and plant-derived proteinase inhibitors

“…Oryzacystatin I (OCI) (Abe et al, 1987) was expressed as s glutathione S-transferase (GST) fusion protein in Escherichia coli strain BL21 (Stratagene) as previously described (Michaud et al, 1994). Aspartyl proteinase inhibitor (API) was purified from potato as previously described (Kreft et al, 1997) and consisted of several isoforms (Ritonja et al, 1990;Barlic-Maganja et al, 1992;Strukelj et al 1992Strukelj et al , 1995Kreft et al, 1997) of potato cathepsin D inhibitor (PDI) (Keilova and Tomasek, 1976b).…”

Proteinase inhibitors and their function in plants: A review

“…Judging from its primary structure, cathepsin D inhibitor (PDI) belongs to the SKTI family [80]. A series of PDI isoforms were subsequently detected [81,82]. Cathepsin D inhibitors similar to PDI were also isolated from the leaves of tomato ( Lycopersicon esculentum L.) [83].…”

Primary Structure of Potato Kunitz-Type Serine Proteinase Inhibitor

“…The specific conformation of the reactive site loop, containing a scissile peptide bond P1-P1Ј, is conserved by a hydrogen bonding network (Onesti et al, 1991). Kunitz-type inhibitors generally have one reactive site, although PIGENI, PCDI, and WCI might have two reactive sites (Shibata et al, 1988;Maganja et al, 1992;Strukelj et al, 1992). Our previous report indicated that PSPI-21 is a double-headed inhibitor.…”

“…They have been found in plants belonging to diverse taxonomic groups (Garcia-Olmedo et al, 1987;Ishikawa et al, 1994;. Potato tubers contain various Kunitz-type proteinase inhibitors with a wide variety of specificities for target enzymes, such as trypsin and/or chymotrypsin inhibitors (Walsh and Twitchell, 1991;Suh et al, 1991), subtilisin inhibitor (Suh et al, 1991), cathepsin D and trypsin inhibitors (Mares et al, 1989;Strukelj et al, 1992), and papain and/or cathepsin L inhibitor (Krizaj et al, 1993). These proteins belong to a subfamily named the potato Kunitz-type proteinase inhibitor (PKPI) family (Ishikawa et al, 1994).…”