Synthesis and characterization of epidermal growth factor-like peptides derived from human blood coagulation factors IX and X.
Item
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Title
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Synthesis and characterization of epidermal growth factor-like peptides derived from human blood coagulation factors IX and X.
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Identifier
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AAI9521324
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identifier
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9521324
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Creator
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Yang, Yan.
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Contributor
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Adviser: William V. Sweeney
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Date
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1995
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Analytical | Chemistry, Biochemistry | Biology, Molecular | Biology, Animal Physiology
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Abstract
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There are four parts in this dissertation. The first chapter mainly reviews the pioneer work by Dr. Cohen's group, who discovered, isolated, and characterized the epidermal growth factor (EGF) molecule. EGF is a 53 residue, cysteine-rich peptide with disulfide pairing Cys 1-3, 2-4 and 5-6. The structural analysis of EGF through CD and NMR has been done, indicating a non-helical structure and two antiparallel {dollar}\beta{dollar}-sheet. The chemical synthesis has been successfully performed by Merrifield's group using a solid-phase method.;The second chapter of the dissertation describes how a two-step approach has been developed to resolve a multiple disulfide scrambling problem in EGF-like peptides. This method reduces the number of possible disulfide isomers from 15 to 3 and has been applied to the C-terminal EGF-like domain in human blood coagulation factor IX (fIX{dollar}\sb{lcub}\rm EGF-C{rcub}{dollar}) and the N-terminal EGF-like domain in factor X (fX{dollar}\sb{lcub}\rm EGF-N{rcub}{dollar}).;Chapter 3 illustrates a characterization of a side reaction found in a synthesis of an EGF-like peptide with Fmoc chemistry. It is the aspartimide formation from -Asp-X-, where X is Asn or Gly. This side reaction was thought not to occur when the side-chain of Asp is blocked with t-butyl which would avoid base-catalyzed aspartimide formation. The formation of aspartimide between two amino acids leads to a formation of a piperidine adduct having an additional mass of 67 u.;Chapter 4 presents a preliminary structural analysis on EGF-like peptides using circular dichroism (CD). The samples include the N-terminal EGF-like domain of human factor IX (fIX{dollar}\sb{lcub}\rm EGF-N{rcub}{dollar}), fX{dollar}\sb{lcub}\rm EGF-N{rcub}{dollar}, fIX{dollar}\sb{lcub}\rm EGF-C{rcub}{dollar}, and a misfolded peptide with the fIX{dollar}\sb{lcub}\rm EGF-C{rcub}{dollar} sequence. Peptides in different oxidized states have been used in this study. The results indicate that at pH 4.2, all the spectra of reduced and oxidized peptides, except that of fully oxidized fIX{dollar}\sb{lcub}\rm EGF-C{rcub}{dollar}, have common CD features, similar to that of oxidized EGF. The CD spectrum of fIX{dollar}\sb{lcub}\rm EGF-C{rcub}{dollar} is completely unlike that of the other EGF-like peptides, suggesting a significantly different structure.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
