Circular dichroism of insulin A chain in water: trifluoroethanol mixtures. Use of linear and nonlinear least squares analysis. 1977

L A Holladay

Circular dichroic spectra obtained for S-carboxymethylated insulin A chain in water: trifluoroethanol mixtures show that a marked conformational transition occurs as the concentration of trifluoroethanol is increased to (v/v) 83% to give a polypeptide containing about 43% of the residues in the alph-helical conformation. Several proposed methods of analysis, including both linear and two nonlinear lest squares methods, were unable to quantitate the amount of beta-structure present in the polypeptide in 83% trifluoroethanol. Examination of the methods of analysis lead to the conclusion that the current models for far UV CD analysis are not adequare for the data obtained in this study and shows that nonlinear least squares procedures may lead to erroneous conclusions.

UI MeSH Term Description Entries
D007328 Insulin A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1). Iletin,Insulin A Chain,Insulin B Chain,Insulin, Regular,Novolin,Sodium Insulin,Soluble Insulin,Chain, Insulin B,Insulin, Sodium,Insulin, Soluble,Regular Insulin
D008433 Mathematics The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed) Mathematic
D011487 Protein Conformation The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain). Conformation, Protein,Conformations, Protein,Protein Conformations
D002942 Circular Dichroism A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed) Circular Dichroism, Vibrational,Dichroism, Circular,Vibrational Circular Dichroism
D003201 Computers Programmable electronic devices designed to accept data, perform prescribed mathematical and logical operations at high speed, and display the results of these operations. Calculators, Programmable,Computer Hardware,Computers, Digital,Hardware, Computer,Calculator, Programmable,Computer,Computer, Digital,Digital Computer,Digital Computers,Programmable Calculator,Programmable Calculators
D012997 Solvents Liquids that dissolve other substances (solutes), generally solids, without any change in chemical composition, as, water containing sugar. (Grant & Hackh's Chemical Dictionary, 5th ed) Solvent
D013056 Spectrophotometry, Ultraviolet Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed) Ultraviolet Spectrophotometry
D013223 Statistics as Topic Works about the science and art of collecting, summarizing, and analyzing data that are subject to random variation. Area Analysis,Estimation Technics,Estimation Techniques,Indirect Estimation Technics,Indirect Estimation Techniques,Multiple Classification Analysis,Service Statistics,Statistical Study,Statistics, Service,Tables and Charts as Topic,Analyses, Area,Analyses, Multiple Classification,Area Analyses,Classification Analyses, Multiple,Classification Analysis, Multiple,Estimation Technic, Indirect,Estimation Technics, Indirect,Estimation Technique,Estimation Technique, Indirect,Estimation Techniques, Indirect,Indirect Estimation Technic,Indirect Estimation Technique,Multiple Classification Analyses,Statistical Studies,Studies, Statistical,Study, Statistical,Technic, Indirect Estimation,Technics, Estimation,Technics, Indirect Estimation,Technique, Estimation,Technique, Indirect Estimation,Techniques, Estimation,Techniques, Indirect Estimation
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