Cytotoxic activity of potato aspartic proteinase could be involves thioredoxin reductase interaction.

· MUÑÓZ F., MENDIETA J.R., PAGANO M.R., DALEO G.R AND GUEVARA M.G.

Pinamar, Buenos Aires, Argentina

Congreso; 10th Congress of Panamerican Association for Biochemistry and Molecular Biology; 2005

Aspartic proteinases (EC 3.4.23) are a class of widely distributed enzymes present in animals, viruses and plants [1]. We have identified and characterized two monomeric potato aspartic proteases from Solanum tuberosum [2] one of them from tuber (StAP1) and other one from leaves (StAP3) [3]. Both StAPs have cytotoxic activity based on the membrane permeabilization of hyphae and spores of Fusarium solani [2], [3], [4]. The majority of plant APs have an internal domain named “plant specific insert” (PSI) [5], this domain has a high homology to saposin like proteins (SAPLIPs). This family of proteins has cytotoxic activity based in the membrane interaction [6] [7] [8]. According with these results, previous evidences suggest that, contrary to heterodymeric, monomeric aspartic proteinases retain the PSI domain in the mature protease [5]. The structural homology between PSI domain and SAPLIPs is based in three conserved disulfide bounds [9]. Previous reports show that DTT have an inhibitory effect on cytotoxic activity of NK-lysin, this result was the start point to analyse the inhibitory effect of a mammalian thiorredoxin reductase on the cytotoxic activity of this enzyme [10] and finished to determinate that S-S bonds are essential in modulating NK-Lysin cytotoxicity. The aim of this work was to study the role of S-S bonds in StAPs cytotoxic activity.Solanum tuberosum [2] one of them from tuber (StAP1) and other one from leaves (StAP3) [3]. Both StAPs have cytotoxic activity based on the membrane permeabilization of hyphae and spores of Fusarium solani [2], [3], [4]. The majority of plant APs have an internal domain named “plant specific insert” (PSI) [5], this domain has a high homology to saposin like proteins (SAPLIPs). This family of proteins has cytotoxic activity based in the membrane interaction [6] [7] [8]. According with these results, previous evidences suggest that, contrary to heterodymeric, monomeric aspartic proteinases retain the PSI domain in the mature protease [5]. The structural homology between PSI domain and SAPLIPs is based in three conserved disulfide bounds [9]. Previous reports show that DTT have an inhibitory effect on cytotoxic activity of NK-lysin, this result was the start point to analyse the inhibitory effect of a mammalian thiorredoxin reductase on the cytotoxic activity of this enzyme [10] and finished to determinate that S-S bonds are essential in modulating NK-Lysin cytotoxicity. The aim of this work was to study the role of S-S bonds in StAPs cytotoxic activity.StAP1) and other one from leaves (StAP3) [3]. Both StAPs have cytotoxic activity based on the membrane permeabilization of hyphae and spores of Fusarium solani [2], [3], [4]. The majority of plant APs have an internal domain named “plant specific insert” (PSI) [5], this domain has a high homology to saposin like proteins (SAPLIPs). This family of proteins has cytotoxic activity based in the membrane interaction [6] [7] [8]. According with these results, previous evidences suggest that, contrary to heterodymeric, monomeric aspartic proteinases retain the PSI domain in the mature protease [5]. The structural homology between PSI domain and SAPLIPs is based in three conserved disulfide bounds [9]. Previous reports show that DTT have an inhibitory effect on cytotoxic activity of NK-lysin, this result was the start point to analyse the inhibitory effect of a mammalian thiorredoxin reductase on the cytotoxic activity of this enzyme [10] and finished to determinate that S-S bonds are essential in modulating NK-Lysin cytotoxicity. The aim of this work was to study the role of S-S bonds in StAPs cytotoxic activity.Fusarium solani [2], [3], [4]. The majority of plant APs have an internal domain named “plant specific insert” (PSI) [5], this domain has a high homology to saposin like proteins (SAPLIPs). This family of proteins has cytotoxic activity based in the membrane interaction [6] [7] [8]. According with these results, previous evidences suggest that, contrary to heterodymeric, monomeric aspartic proteinases retain the PSI domain in the mature protease [5]. The structural homology between PSI domain and SAPLIPs is based in three conserved disulfide bounds [9]. Previous reports show that DTT have an inhibitory effect on cytotoxic activity of NK-lysin, this result was the start point to analyse the inhibitory effect of a mammalian thiorredoxin reductase on the cytotoxic activity of this enzyme [10] and finished to determinate that S-S bonds are essential in modulating NK-Lysin cytotoxicity. The aim of this work was to study the role of S-S bonds in StAPs cytotoxic activity.StAPs cytotoxic activity.