RESUMEN
[chemical structure: see text]. C60H18 has been produced by hydrogenation of C60 at 100 bar H2 pressure and 673 K for 10 h. We have investigated the crude material without any purification by use of 1H NMR, 13C NMR, and IR spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry. We show that the crude material consists of 95% of the C3v isomer of C60H18.
RESUMEN
Fourier self-deconvolution was applied to the infrared spectra of five globular proteins with a high beta-structure content and to the essentially alpha-helical protein hemoglobin. The featureless amide I' bands around 1650 cm-1 were thereby resolved into six to nine components, depending on the protein. Specific components were assigned to the beta-structure segments in each protein. The frequencies and the number of 'beta-bands' differ from one protein to another. The areas of the components were evaluated by means of a Gauss-Newton iteration procedure. It appears that the total area of the beta-bands, as a fraction of the total amide I' band area, reflects the relative beta-structure content of each protein studied.
Asunto(s)
Conformación Proteica , Amidas/análisis , Quimotripsina/análisis , Quimotripsinógeno/análisis , Concanavalina A/análisis , Análisis de Fourier , Hemoglobinas/análisis , Ribonucleasa Pancreática/análisis , Ribonucleasas/análisis , Espectrofotometría Infrarroja/métodosRESUMEN
Fourier self-deconvolution of Fourier transform infrared (FTIR) spectra and second derivative FTIR spectroscopy were applied to study solvent-induced conformational changes in globular proteins. For beta-lactoglobulin a total of three different denatured forms were identified in alkaline solution and in aqueous methanol-d1 and isopropanol-d1. In isopropanol-d1 solution a new conformation was identified which appears to resemble, but is not identical with, the beta-structure of native proteins. This conformation is characterized by absorption bands around 1615-1618 and 1684-1688 cm-1, and is also observed for concanavalin A and chymotrypsinogen A in aqueous isopropanol-d1 solution.
Asunto(s)
Desnaturalización Proteica , Espectrofotometría Infrarroja/métodos , Animales , Bovinos , Quimotripsinógeno , Concanavalina A , Análisis de Fourier , Lactoglobulinas , Conformación Proteica , SolventesRESUMEN
A new rapid method for the quantitative and routine determination of free amino groups in intact pure proteins has been developed. Primary amino groups are labeled with fluorescamine and the labeled groups are detected by absorption spectroscopy in the range 375-390 nm. The amino group concentration can be determined in a few minutes without hydrolyzing the labeled protein and extracting a lysine derivative. The method was tested with the following proteins: lysozyme, alpha-lactalbumin, beta-lactoglobulin, bovine serum albumin, ribonuclease, ribonuclease-S-peptide, and alphasl-casein B. Application of this method to the estimation of available lysine is discussed.
