Main description:

The properties of proteins are determined not only by the sequence of amino-acid residues in the polypeptide chains, but also by the con figuration of the chains-the way in which the chains are coiled or folded. It is probable that denaturation, the loss of some of the specific properties of a native protein, may in many cases be the result simply of a change in configuration of the polypeptide chains, without any change whatever in the sequence of amino-acid residues. During the past few years great progress has been made in the attack on the determination of the sequence of amino-acid residues in the poly peptide chains of proteins, through the work of SANGER and his collabora tors (Io9, IIO) and of other investigators. There has also been significant progress in the attack on the problem of the configuration of polypeptide chains, largely through the application of the X-ray diffraction technique.

Contents:

/ Contents / Table des matieres.- Starch: Its Constitution, Enzymic Synthesis and Degradation.- I. Introduction.- II. Chemical Investigations of the Basic Structure of Starch.- 1. End-Group Assay.- 2. The Molecular Size of Starch.- III. Amylose and Amylopectin.- 1. Separation.- 2. Comparison of Properties.- a) Solubility.- b) Degree of Polymerisation.- c) Percentage of Non-reducing End-Groups.- d) Reaction with Iodine.- e) Crystallinity.- 3. The Amylose-Amylopectin Ratio.- IV. Structure of Amylose.- 1. Molecular Size.- 2. Evidence from Amylolysis.- 3. Z-Enzyme.- 4. The Maltosaccharides.- V. Structure of Amylopectin.- 1. Molecular Size and Degree of Branching.- 2. Nature of the Branch Link.- 3. R-Enzyme, a Debranching Enzyme.- 4. Conformation of the Amylopectin Molecule.- VI. Enzymic Synthesis of Starch.- 1. Synthesis of Amylose.- a) The Donor.- b) The Acceptor.- c) The Enzyme.- 2. The Synthesis of Amylopectin.- a) The Branching Enzyme.- b) The Mechanism of Branching.- c) Substrate for Q-Enzyme.- d) Q-Enzyme, a Transglucosylase.- e) The Acceptor.- f) D-Enzyme.- References.- Neuere Ergebnisse auf dem Gebiete des Lignins und der Verholzung.- I. Einleitung.- II. Der Stoff.- III. Analyse und Reaktionen.- IV. Abbau.- V. Modellsubstanzen.- VI. Optisches Verhalten.- VII. Biosynthese des Lignins.- VIII. Vorstufen der Ligninbildung. Die sekundaren Bausteine.- IX. Verknupfung der sekundaren Bausteine zum Lignin.- X. Beziehung der naturlichen Ligninarten untereinander und zum kunstlichen Lignin.- XI. Die Bindung des Lignins im Holze.- XII. Der Vorgang der Verholzung.- XIII. Schlusswort.- Probleme und neuere Ergebnisse in der Vitamin D-Chemie.- I. Pracalciferol, ein neues Isomeres in der Reihe der Bestrahlungsprodukte des Ergosterins.- II. Konstitution des Vitamins D2 und des Tachysterins.- III. Zusammenfassung neuerer Einzelergebnisse aus der Chemie der Vitamine und Provitamine D.- 1. Neue Verbindungen des Vitamins D2.- 2. Neuere Methoden zur Darstellung von Provitaminen und Vitaminen D.- 3. Neue Vitamine D und Beitrage zum Zusammenhang zwischen Konstitution und physiologischer Wirkung.- IV. Ozon-Abbau des Vitamins D2 ; zugleich ein Beitrag zur Stereochemie der Steroide.- V. Isomerisierung des Vitamins D2.- VI. Synthetische Versuche in der Vitamin D-Reihe.- 1. Modellversuche zur Darstellung Vitamin D-ahnlicher Substanzen.- 2. Partialsynthese von zwei neuen Isomeren des Vitamins D2.- 3. Syntheseversuche des C,D-Hydrindan-Ringsystems.- VII. Photodehydro-ergosterin.- VIII. Schlusswort.- Naturlich vorkommende Chromone. (Mit Anhang uber weitere Eleutherine-Inhaltsstoffe.).- I. Einleitung.- II. Pflanzlicher Ursprung und Isolierung der Chromone.- Ammi visnaga.- Peucedanum Ostruthium.- Eugenia caryophyllata.- Eleutherine bulbosa.- Isolierung der Chromone.- III. Konstitutionsermittlung der Chromone.- 1. Allgemeine Bemerkungen.- Abbau mit Alkali.- Reaktionen der 2-standigen Methylgruppe.- Farbreaktionen.- Reaktion mit Carbonylreagenzien.- 2. Spezieller Teil.- Chromone aus Eugenia caryophyllata: Eugenin.- Eugenitin.- Isoeugenitin.- Isoeugenitol.- Umlagerungen mit Jodwasserstoffsaure.- Chromon aus Peucedanum Ostruthium: Peucenin.- Chromone aus Ammi visnaga: Khellin.- Visnagin.- Visamminol.- Khellinol.- Khellolglucosid, Khellol.- Konstitution und U. V.-Absorptionsspektren von ?-Benzopyronen.- Chromon aus Eleutherine bulbosa: Eleutherinol.- IV. Synthese der naturlichen Chromone und verwandter Verbindungen.- 1. Allgemeine Bemerkungen.- 2. Spezieller Teil.- Chromone aus Eugenia caryophyllata.- Peucenin.- Khellin und Khellinon.- Khellol.- Visnagin, Visnaginon und verwandte Verbindungen.- Isovisnagin.- Allovisnagin.- Weitere Furo- und Dihydrofuro-chromone.- V. Zur Biogenese der Chromone.- VI. Pharmakologie und therapeutische Anwendung einiger Chromone.- Khellin.- Visnagin.- Khellol-glucosid.- Visamminol.- Khellinol.- Visnagan.- Klinische Verwendung von Khellin.- VII. Zusammenhange zwischen Konstitution und pharmakologischer Wirksamkeit von Chromonen.- Anhang: VIII. Weitere Inhaltsstoffe aus Eleutherine bulbosa und einige damit verwandte Verbindungen.- Eleutherol.- ?-Sorinin und ?-Sorigenin.- ?-Sorinin und ?-Sorigenin.- Weitere naturliche Naphthaline.- Eleu-therine-chinone und Fusarubin: Eleutherin.- Isoeleutherin.- Allo-eleutherin.- Alloiso-eleutherin.- Konfigurative Zusammenhange.- Fusarubin.- The Configuration of Polypeptide Chains in Proteins.- I. The Dimensions of the Amide Group.- 1. The Amino Acids.- a) The Crystal Structure of L-Hydroxyproline.- b) The Crystal Structure of DL-Serine.- 2. Simple Peptides and Related Substances.- a) The Crystal Structure of ?-Glycyl-glycine.- b) The Crystal Structure of N,N'-Diglycyl-L-cystine Dihydrate.- c) The Crystal Structure of Glycyl-L,-asparagine.- d) The Crystal Structure of Glycyl-L-tryptophan Dihydrate.- 3. The Configuration of the Amide Group.- a) Dimensions of the Amide Group.- b) Effects of Resonance.- c) Properties of N-H * * * O Hydrogen Bonds.- d) Estimations of Stabilization and Strain Energies.- II. Helical Configurations of Polypeptide Chains.- 1. The ? Helix.- 2. The ? Helix and Other Helixes.- III. Sheets of Polypeptide Chains.- IV. The Structure of Fibrous Proteins.- 1. The Structure of the ?-Keratin Proteins.- a) Some Interpretations of the X-ray Pattern.- b) The Occurrence of the ? Helix.- A. Synthetic Polypeptides.- B. The ?-Keratin Proteins.- 2. The Structure of Silk and the ?-Keratin Proteins.- 3. Collagen and Gelatin.- V. The Structure of Globular Proteins.- References.- Column Chromatography in the Study of the Structure of Peptides and Proteins.- I. The Separation of Amino Acids and the Determination of the Amino Acid Composition of Peptides and Proteins.- 1. Analytical Determination of Amino Acids by Chromatography.- a) Separation of Amino Acids on Starch.- b) Separation of Amino Acids on Ion Exchange Resins.- c) Comparison and Discussion of Starch and Ion Exchange Methods.- d) Application of Starch and Ion Exchange Methods to the Analysis of Peptides and Proteins.- 2. Isolation of Amino Acids by Chromatography.- a) Method of Hirs, Moore, and Stein.- b) Method of Partridge and Collaborators.- c) Miscellaneous Isolative Methods.- 3. Conclusions.- II. The Determination of Amino Acid Sequence in Proteins. The Identification of Terminal Residues and the Separation and Identification of Peptides.- 1. Identification of N-Terminal Amino Acids.- a) Sanger's Method : The Use of 2,4-Dinitrofluorobenzene.- b) Edman's Method: The Use of Phenylisothiocyanate.- c) Other Methods.- d) Conclusions.- 2. Identification of C-Terminal Amino Acids.- a) The Schlack and Kumpf Method.- b) The Carboxypeptidase Method.- c) Reduction Methods.- d) The Hydrazinolytic Method.- e) Conclusions.- 3. The Separation and Identification of Peptides.- a) The Separation of Free Peptides.- b) The Separation of DNP-Peptides.- c) The Identification of Peptides.- d) Conclusions.- III. The Separation and Purification of Proteins.- IV. Concluding Remarks.- References.- Porphyrins in Nature.- I. Introduction.- II. The Structure of the Porphin Nucleus.- III. The Naturally Occurring Porphyrins.- IV. Methods of Isolation, Separation, Identification and Estimation.- Isolation of Porphyrins from Natural Sources.- Separation.- Solubility.- HCl-Method.- Crystallisation.- Chromatography.- Identification of Porphyrins.- Absorption Spectra.- Fluorescence Spectra.- Estimation.- V. Individual Porphyrins.- Protoporphyrin "IX".- Mesoporphyrin "IX".- Deuteroporphyrin "IX".- Haematoporphyrin "IX".- Chlorocruoroporphyrin.- Porphyrin a (Cytoporphyrin).- Cryptoporphyrins.- Mono-, Di-, and Tricarboxylic Porphyrins of Unknown Structure.- Coproporphyrins.- Porphyrins with five to seven Carboxyl Groups.- Uroporphyrins.- Colourless Precursors of Uroporphyrins.- Porphyrins derived from Chlorophyll.- VI. The Biosynthesis of Porphyrins.- VII. The Biosynthesis of Chlorophyll.- VIII. Porphyrins are not Intermediates in the Catabolism of Haem Compounds.- References.- The Pteridines.- I. Introduction.- II. Simple Mono- and Di-substituted Pteridines as Models for the Understanding of Naturally-occurring Pteridines.- 1. Solubility and Fusibility.- 2. Stability to Acids and Alkalis.- 3. Ionization; Metal-binding Properties.- 4. Spectra.- 5. Chemical Reactions.- III. The Naturally-occurring Pteridines (excluding the Folic Acid Series).- 1. Glossary of Synonyms.- 2. The Xanthopterin Family: Xanthopterin, Chrysopterin, Erythropterin.- Xanthopterin.- Chrysopterin.- Erythropterin.- 3. The isoXanthopterin Family: isoXanthopterin, Ichthyopterin, Fluorescyanine and Leucopterin.- isoXanthopterin.- Ichthyopterin.- Fluorescyanine.- Leucopterin.- 4. Substances closely Related to the Naturally-occurring Pteridines: Pterorhodin, Urothion.- Pterorhodin.- Urothion.- IV. The Folic Acid Series.- 1. The Synthesis of Pteroylglutamic Acid ("PGA").- 2. The Occurrence and Properties of Pteroylglutamic Acid.- 3. Conjugates of Pteroylglutamic Acid.- 4. Rhizopterin.- 5. The Citrovorum Factor and Leucovorin.- 6. New Members of the Folic Acid Series.- V. Substances which are Presumably Pteridines.- VI. Chromatography and other Techniques of Isolation and Purification.- VII. The Physiological Action of the Natural Pteridines.- The Simpler Pteridines.- The Folic Acid Series.- References.- Namenverzeichnis. Index of Names. Index des Auteurs.- Sachverzeichnis. Index of Subjects. Index des Matieres.