Isolation and characterization of tepary bean proteinase inhibitors and their nutritional and physiological significance.

Persistent Link:
http://hdl.handle.net/10150/186979
Title:
Isolation and characterization of tepary bean proteinase inhibitors and their nutritional and physiological significance.
Author:
Osman, Magdi Abedel Whab.
Issue Date:
1994
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
A protein inhibitor of bovine trypsin and chymotrypsin has been purified from tepary bean (Phaseolus acutifolius) using salt extraction and ammonium sulfate precipitation followed by ion exchange chromatography, hydrophobic chromatography and gel permeation chromatography. Tepary proteinase inhibitor has a molecular weight of 17,500 daltons as measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and gel permeation chromatography. Amino acid analysis showed a high content of half-cystine, aspartic acid, serine and glutamic acid residues. The amino-terminal amino acid sequence of the inhibitor revealed high homology to the Bowman-Birk inhibitor family. The tepary proteinase inhibitor has antiproteinase activities similar to those of legume inhibitors of serine proteinase with inhibition of trypsin and chymotrypsin, but not pepsin. Other properties shared with the Bowman-Birk inhibitors include acid and heat resistance, and the presence of two distinct reactive sites, one for trypsin and another for chymotrypsin as indicated by chemical modification of the inhibitor. A similar trypsin and chymotrypsin inhibition was found in a tepary prolamine fraction having a molecular weight of 17,700 daltons estimated by SDS-PAGE and gel permeation chromatography. The amino acid composition of this inhibitor closely resembles those of the low molecular weight Bowman-Birk inhibitors of other legumes. A thermal inactivation study showed that tepary proteinase inhibitor was extremely heat stable at neutral and acidic pH, but heat labile at alkaline pH, similar to the soybean Bowman-Birk and lima bean trypsin inhibitors. Inclusion of tepary bean proteinase inhibitor in diets containing whole egg as the source of dietary protein (8%) significantly reduced growth rate, protein efficiency ratio and protein digestibility, and caused pancreatic hypertrophy in mice.
Type:
text; Dissertation-Reproduction (electronic)
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Nutritional Sciences; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Weber, Charles W.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleIsolation and characterization of tepary bean proteinase inhibitors and their nutritional and physiological significance.en_US
dc.creatorOsman, Magdi Abedel Whab.en_US
dc.contributor.authorOsman, Magdi Abedel Whab.en_US
dc.date.issued1994en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractA protein inhibitor of bovine trypsin and chymotrypsin has been purified from tepary bean (Phaseolus acutifolius) using salt extraction and ammonium sulfate precipitation followed by ion exchange chromatography, hydrophobic chromatography and gel permeation chromatography. Tepary proteinase inhibitor has a molecular weight of 17,500 daltons as measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and gel permeation chromatography. Amino acid analysis showed a high content of half-cystine, aspartic acid, serine and glutamic acid residues. The amino-terminal amino acid sequence of the inhibitor revealed high homology to the Bowman-Birk inhibitor family. The tepary proteinase inhibitor has antiproteinase activities similar to those of legume inhibitors of serine proteinase with inhibition of trypsin and chymotrypsin, but not pepsin. Other properties shared with the Bowman-Birk inhibitors include acid and heat resistance, and the presence of two distinct reactive sites, one for trypsin and another for chymotrypsin as indicated by chemical modification of the inhibitor. A similar trypsin and chymotrypsin inhibition was found in a tepary prolamine fraction having a molecular weight of 17,700 daltons estimated by SDS-PAGE and gel permeation chromatography. The amino acid composition of this inhibitor closely resembles those of the low molecular weight Bowman-Birk inhibitors of other legumes. A thermal inactivation study showed that tepary proteinase inhibitor was extremely heat stable at neutral and acidic pH, but heat labile at alkaline pH, similar to the soybean Bowman-Birk and lima bean trypsin inhibitors. Inclusion of tepary bean proteinase inhibitor in diets containing whole egg as the source of dietary protein (8%) significantly reduced growth rate, protein efficiency ratio and protein digestibility, and caused pancreatic hypertrophy in mice.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineNutritional Sciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairWeber, Charles W.en_US
dc.contributor.committeememberReid, Bobby L.en_US
dc.contributor.committeememberSheehan, Edward T.en_US
dc.contributor.committeememberHewlett, Martyen_US
dc.contributor.committeememberPrice, Ralph L.en_US
dc.identifier.proquest9517589en_US
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