Temperature Behaviour of Human Serum Albumin WETZEL, Rolf; BECKER, Manfred; BEHLKE, Joachim ...
European journal of biochemistry,
March 1980, Volume:
104, Issue:
2
Journal Article
Peer reviewed
Open access
Structural alterations of albumin, their dependence on concentration and the role of free ‐SH groups at thermal denaturation, as well as the reversibility of thermally induced structural changes, ...were studied. Application of various physical methods provides information on a series of structural parameters in a major concentration range. Apart from changes of the helix content, heat treatment gives rise to β structures which are amplified on cooling and which are correlated with the aggregation of albumin. With rising temperature and concentration the proportion of β structures and aggregates increases.
At degrees of denaturation of up to 20% complete renaturation is possible in every case. The structure content is concentration‐dependent even at room temperature. It may be that intermolecular interactions induce additional α‐helix structures which are less stable, however, than the ones stabilized by intramolecular interactions. Unfolding of the pocket containing the free ‐SH group of cysteine‐34 enables disulphide bridges to be formed leading to stable aggregates and irreversible structural alterations. Through binding of N‐ethylmaleimide to free ‐SH groups, which blocks the formation of disulphide bridges, it is possible to prevent aggregation and irreversible conformational changes. At temperatures below 65–70°C, oligomers are formed mainly via intermolecular β structures.
We present the Data Release 12 Quasar catalog (DR12Q) from the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey III. This catalog includes all SDSS-III /BOSS objects ...that were spectroscopically targeted as quasar candidates during the full survey and that are confirmed as quasars via visual inspection of the spectra, have luminosities Miz = 2 < -20.5 (in a Lambda CDM cosmology with H-0 = 70 km s (1) Mpc (1), Omega(M) = 0 : 3, and Omega(A) = 0.7), and either display at least one emission line with a full width at half maximum (FWHM) larger than 500 km s (1) or, if not, have interesting /complex absorption features. The catalog also includes previously known quasars (mostly from SDSS-I and II) that were reobserved by BOSS. The catalog contains 297 301 quasars (272 026 are new discoveries since the beginning of SDSSIII) detected over 9376 deg(2) with robust identification and redshift measured by a combination of principal component eigenspectra. The number of quasars with z > 2.15 (184 101, of which 167 742 are new discoveries) is about an order of magnitude greater than the number of z > 2 : 15 quasars known prior to BOSS. Redshifts and FWHMs are provided for the strongest emission lines (C iv, C III, Mg II). The catalog identifies 29 580 broad absorption line quasars and lists their characteristics. For each object, the catalog presents five-band (u, g, r, i, z) CCD-based photometry with typical accuracy of 0.03 mag together with some information on the optical morphology and the selection criteria. When available, the catalog also provides information on the optical variability of quasars using SDSS and Palomar Transient Factory multi-epoch photometry. The catalog also contains X-ray, ultraviolet, near-infrared, and radio emission properties of the quasars, when available, from other large-area surveys. The calibrated digital spectra, covering the wavelength region 3600-10 500 a at a spectral resolution in the range 1300 < R < 2500, can be retrieved from the SDSS Catalog Archive Server. We also provide a supplemental list of an additional 4841 quasars that have been identified serendipitously outside of the superset defined to derive the main quasar catalog.
