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  • TITLE
  • DEDICATION
  • CERTIFICATE
  • DECLARATION
  • ACKNOWLEDGEMENT
  • CONTENTS
  • ABBREVIATIONS
  • I. INTRODUCTION AND OBJECTIVES
  • OBJECTIVES OF THE PRESENT WORK
  • 1. Correlation of the macromolecular structural parameters with the reactivity of the functional groups relevant for peptide synthesis.
  • 2. Probing the optimum conditions for effective synthetic converaions
  • 3. Delineation of the structural paremeters for efficient supports and illustration of the application of suitable resins for peptide synthesis.
  • SUMMARY OF RESULTS
  • i. Synthesis of acrylamide-based polymeric supports
  • ii. Polymer reactivity
  • iii. Water-binding studies and hydrophilicity scale of the polymer supports
  • iv. Polysterene-based supports
  • v. Peptide synthesis
  • OROANISATION OF THE THESIS
  • II. SOLID PHASE PEPTIDE SYNTHESIS: AN OVERVIEW
  • 1. Chemical synthesis of peptides
  • 2. Solid phase peptide synthesis
  • 3. Problems involved in solid phase peptide synthesis
  • 4. Recent trends in solid phase peptide synthesis
  • 5. Solvation within the solid phase
  • Fig. 11. 2. Hypothetical models of polystyrene-bound peptides
  • 6. Incomplete coupling and deprotection reactions
  • 7. Impact of secondary structure formation during synthesis
  • 8. Non-equivalence of reaction sites
  • 9. Optimization of the polymer support
  • 10.Effect of macromolecular matrix
  • 11. Molecular character and extent of cross linking
  • III. MACROMOLECULAR SYSTEMS SELECTED AND METHODOLOGY: SYNTHETIC AND PHYSICOCHEMICAL STUDIES
  • 1. Polymer synthesis
  • a. Poly (acrylamide) s cross linked with N, Nmethylene bisacrylamide
  • b. Poly (acrylamide) s crosslinked with tetraethyleneglycol diacrylate
  • c. Poly (acrylamide) s cross linked with triethyleneglycol dimethacrylate
  • d. Poly (acrylamide) s cross linked with divinylbenzene
  • e. Terpolymers of acrylamide, N, N--dimethylacrylamide and N, N-metbylene bisacrylamide
  • f. Terpolymers of acrylamide, N, N—dimethylacrylamide and divinylbenzene
  • g. Poly (styrene) s crosslinked with triethyleneglycol dimethacrylate
  • 2. Functionalisation of the cross linked polymers
  • a. Transamidation of crosslinked poly (acrylamide) s to poly (N-2-aminoethylacrylamide) s
  • b. Transamidation of poly (acrylamide) s to poly (N-2-aminohexylacrylamide) s
  • c. Functionalisation of crosslinked poly (styrene) s by chloromethylation
  • 3. Functional group analysis
  • a. Amino capacity
  • b. Extent of chloromethylation
  • 4. Reactivity studies
  • a. Effect of nature of monomers and resulting polymeric system on reactivity
  • b. Effect of nature of crosslinking agent
  • c. Effect of degree of crosslinking
  • d. Effect of solvent
  • e. Effect of spacer on reactivity
  • 5. Swelling and solvation
  • a. Polyacrylamide-based resins
  • b. Polystyrene-TEGDMA resins
  • 6. Water binding studies
  • a. Equilibrium water content
  • i. Effect of nature of monomers and cross linking agent on EWC
  • ii. Effect of degree of crosslinking
  • iii. Effect of method of polymerisation
  • iv. Effect of temperature on water sorption
  • v. Time-course of hydration: effect of degree. of crosslinks
  • b. Desorption kinetics
  • Effect of crosslink density on desorption kinetics
  • c. Water structuring in poly (acrylamide) gels
  • d. Weight percent oxygen content
  • e. Water-swollen poly (acrylamide) s: physical nature and mechanical characteristics
  • 7. Morphological studies
  • a. Effect of crosslinking agent on morphology
  • Fig. III. 3 5. (a,b) Scanning Electron Micrographs of 10% NNMBA- crosslinked poly (acrylamide) s
  • Fig. III. 36 (a,b) Scaning Electron Micrographs of 10% TTEGDA- crosslinked poly (acrylamide) s
  • Fig. III. 3 7. (a,b) Scanning Electron Micrographs of 10% TEGDMA- crosslinked poly (acrylamide) s
  • Fig. III. 38. (a,b) Scanning Electron Micrographs of 10% DVB- crosslinked poly (acrylamide) s
  • b. Effect of extent of crosslinking on morphology
  • Fig. III. 39 Scanning Electron Micrographs of (a) 5% and (b) 10% TTEGDA- crosslinked poly (acrylamide) s
  • c. Linear Vs. crosslinked poly (acryl amides)
  • Fig. III. 40 Scanning Electron Micrographs of (a) 15% and (b) 20% TTEGDA- crosslinked poly (acrylamide) s
  • Fig. III. 41. Scanning Electron Micrographs of (a) linear poly (acrylamide) and (b) 5% TTEGDA crossliked poly (acrylamide)
  • d. Effect of addition of a third component: terpolymerisation and subsequent morphology
  • e. Effect of method of polymerisation on morphology
  • Fig. III. 42. Scanning Electron Micrographs of (a) 10% DVB- crosslinked acrylamide-dimethylacrylamide terpolymer and (b) acrylamide copolymer
  • Fig. III. 43 Scanning Electron Micrographs of 10% NNMBA crosslinked acrylamide prepared (a) in bulk and (b) in film form
  • f. Effect of functionalisation on morphology
  • Fig. III. 44. (a,b) Scanning Electron Micrographs of 10% TTEGDA- crosslinked poly (acrylamide) in film form
  • Fig. III. 45. Scanning Electron Micrographs of 10% TTEGDA- crosslinked poly (acrylamide) after functionalisation with ethylenediamine
  • g. Morphology of poly (styrene) -TEGDMA resins
  • Fig. III. 46. (a,b) Scanning Electron micrographs of 2% TEGDMA- crosslinked poly (styrene) beads
  • 8. Thermal stability of the polymeric supports
  • a. Effect of nature of crosslinking
  • b. Effect of polymerisation conditions
  • c. Effect of addition of a third component
  • IV. SYNTHESIS OF MODEL PEPTIDES AND BIOACTIVE PEPTIDES
  • 1. Preparation of 4-bromomethyl benzoyl amino ethylpoly (acrylamide)
  • 2. Synthesis of Gly-Ala
  • 3. Synthesis of Ala-Ala-Gly-Gly
  • 4. Synthesis of Phe-Leu-Leu
  • Synthesis of biologically relevant sequences
  • 5. Synthesis of Crabrolin: Phe-Leu-Pro-Leu-Ile Leu-Arg-Lys-Ile-Val-Thr-Ala-Leu -a peptide toxin
  • 6. Problems encountered in the synthesis
  • 7. Synthetic attempts with other acrylamide based supports
  • 8. Gisins method Vs. triethylammonium salt method for C-terminal amino acid attachment
  • 9. Attempt to attach the first amino acid as its acid chloride
  • 10. Inherent problems with the acrylamide-based supports
  • 11. Cross linked terpolymers of acrylamide and N, N-dimethylacrylamide as supports
  • 12. Synthesis of a drug targeting tetrapeptide: Ala-Leu-Ala-Leu
  • a. The polymer support for peptide synthesis
  • b. Deprotection and cleavage
  • c. purification by FPLC
  • d. Amino acid analysis
  • 13. Synthesis of human growth hormone releasing factor (hGRF) segment (12-15): Lys-Leu-Val-Gly
  • a. Peptide Synthesis
  • b. Assembly of Lys-Val-Leu-Gly (K V L G)
  • c. Deprotection and cleavage
  • d. Purification of the crude peptide
  • Fig. IV. 6. Scanning Electron Micrographs of chloromethylcopoly (PS-2%-TEGDMA) resin (a) before synthesis (b) after synthesis.
  • e. Amino acid analysis
  • 14. Synthesis of a contraceptive tetrapeptide: Thr-Pro-Arg-Lys
  • a. Attachment of Boc (C12) - Lysine to chloromethyl resin
  • b. Syntheels of Thr-Pro-Arg-Lys (T P R K)
  • d. Cleavage and purification
  • e. Amino acid analysis
  • 15. Synthesis of a delicious octapeptide: Lys-Gly Asp--Glu--Glu-Ser-Leu-Ala
  • a. Assembly of the peptide Lys-Gly-Asp-Glu-Glu-Ser-Leu-Ala (K G D E E S L A)
  • b. Cleavage of the peptide, purification and amino acidanalysis
  • 16. Synthesis of seminalplasmin segment (14-26): Ser--Leu-Ser-Arg-Tyr-Ala-Lys-Leu-Ala-Asn-Arg Leu-Ala
  • a. Peptide Synthesis
  • b. Purification of the peptide
  • c. Analysis of the peaks
  • d. Manual microsequencing of seminalplasmin segment
  • e. Circular dichroism spectra of Ser-Leu-Ser-Arg-Tyr-Ala-Lys-Leu-Ala-Asn-Arg-Leu-Ala
  • 17. Synthesis of seminalplasmin segment (28-40): Pro-Lys-Leu-Leu-Lys-Thr-Phe-Leu-SerLys-Trp Ile-Gly
  • a. Synthesis of Pro-Lys-Leu-Leu-Lys-Thr-Phe-Leu-Ser-Lys-Trp-Ile-Gly
  • b. Cleavage, purification and amino acid analysis
  • c. Sequencing of the peptide
  • d. CD studies
  • e. Biological activity
  • f. Stability of the PS-TEGDMA support
  • V. EXPERIMENTAL
  • Part A. Preparation of polymers and functionalisation Materials and methods
  • 1. Source of chemicals
  • 2. Polymer synthesis
  • a. NNMBA- crosslinked poly (acrylamide) e: general procedure
  • b. TTEODA- crosslinked poly (ecrylamide) s: general procedure
  • c. TEGDMA- crosslinked poly (acrylamide) s: general procedure
  • d. DVB- crosslinked poly (acrylamide) s: genera1 procedure
  • e. NNMBA- crosslinked acrylamide- N, N-dimethylacrylamide terpolymer by inverse suspension polymerisation
  • f. DVB- crosslinked terpolymers of acrylamide and N, N-dimethylacrylamide
  • g. TEGDMA- crosslinked poly (styrene) s by suspension polymerisation
  • h. Prepration of NNMBA- crosslinked polyIacrylamide) s in film form
  • i. Preparation of TEGDMA- crosslinked poly (acrylamide) in film form
  • 3. Amino functionalisation
  • 4. Preparation of anhydrous zinc chloride in THF
  • 5. Preparation of chloromethyl methylether
  • 6. Estimation of capacity
  • 7. Preparation of N-benzoylglycine 4-nitrophenyl ester
  • 8. Aminolysis of polymeric amines by the active ester
  • 9. Estimation of functional group reactivity towards peptide coupling
  • 10. Swelling and solvation
  • 11. Determination of equilibrium water content of crosslinked poly (acrylamide) s
  • 12. Estimation of freezing and non-freezing water content
  • 13. Water sorption / desorption experiments
  • 14. Polymer morphological studies
  • 15. Thermal stability of the supports
  • Part B. Peptide synthesis
  • 16. Source of chemicals
  • 17. Physical measurements
  • 18. Purification of reagents and solvents
  • 19. Detection
  • i. Thin layer chromatography
  • ii. Identification of the peotide on TLC
  • 20. Visualisation
  • 21. Amino acid analysis
  • 22. Preparation of derivatives
  • a. Preparation of Boc azide from t-butyl carbazate
  • b. Synthesis of Boc amino acids by Schnabels method
  • c. Boc-ON method: general Procedure
  • d. Purity of Boc amino acids
  • 23. Methods of coupling
  • a. Dicyclohexylcarbodiimide method
  • b. Active ester method
  • 24. General method for solid phase peptide synthesis
  • 25. Deprotection procedure
  • 26. Purification
  • a. Column chromatography
  • b. Fast protein liquid chromatography
  • 27. Amino acid analysis
  • 28. Peptide sequencing
  • 29. Circular dichroism measurement
  • 30. Preparation of 4-bromomethyl benzoic acid from 4-methyl benzoic acid
  • 31. Preparation of 4-methyl benzoyl chloride from 4-bromomethyl benzoic acid
  • 32. Preparation of 4-bromomethyl benzoyl aminoethyl DVB-crosslinked poly (acrylamide)
  • 33. Estimation of bromine content in the bromo resin
  • 34. Capping the residual amino groups by acetylation
  • 35: Attachment of the first amino acid to the bromo resin via esterification
  • 36. Attachment of first Boc amino acid by Gisins cesium salt method
  • 37. Estimation of first amino acid substitution by picric acid method
  • 38. Preparation of 4N HCI / dioxane
  • 39. Synthesis of Ala-Leu-Ala-Leu
  • a. Preparation of cesium salt of Boc-Leu
  • b. Attachment of Boc-Leu to chloromethyl resin
  • c. Synthesis of Ala-Leu-Ala-Leu (A L A L)
  • d. Cleavage, purification and amino acid analysis
  • e. Amino acid analysis
  • 40. Synthesis of Lys-Val-Leu-Gly
  • a. Attachment of the first amino acid to the functionalised resin
  • b. Stepwise synthesis of hQRF segement (12-15)
  • c. Cleavage of the peptide
  • d. Purification and analysis
  • 41. Synthesis of Thr-Pro-Arg-Lys
  • a. Attachment of first amino acid to chloromethyl resin and estimation of the level of substitution
  • b. Synthesis of Thr-Pro-Arg-Lys (TPRK)
  • c. Deprotection and cleavage
  • d. Purification and amino acid analysis
  • 42. Synthesis of Lys-Gly-Asp-Glu-Glu-Ser-Leu-Ala
  • a. Attachment of the first amino acid to the chloromethyl resin
  • b. Stepwise addition of Boc-Amino acids
  • c. Cleavage of the finished peptide from petidyl resin
  • d. Purification of crude peptide
  • e. Amino acid analysis
  • 43. Synthesis of Ser-Leu-Ser-Arg-Tyr-Ala--Lys-Leu Ala-Asn-Arg-Leu-Ala
  • a. Attachment of the C-terminal aminoacid to the functionalised resin
  • b. Stepwise synthesis of the peptide
  • c. Cleavage of the finished peptide from the resin
  • d. Purification of the peptide
  • e. Manual microsequencing of seminalplasmin (14-28)
  • f. CD studies
  • 44. Synthesis of Pro--Lys-Leu-Leu-Lys-Thr-Phe-Leu Ser-Lys-Trp-Ile-Gly
  • a. Attachment of the first amino acid and synthesis of SPF (28-40)
  • b. Cleavage of the peptide from the resin support
  • c. Purification of the crude peptide
  • d. Amino acid analysis
  • e. Amino acid Sequencing
  • f. CD Spectrum
  • VI. SUMMARY AND OUTLOOK
  • VII. REFERENCES