The structure of globular proteins and their interactions with the external medium—III. Effect of disulfide bonds on the configuration and solubility of serum albumin

1962 ◽  
Vol 3 (1) ◽  
pp. 155-156
Keyword(s):  
Serum Albumin ◽  
Disulfide Bonds ◽  
External Medium ◽  
Globular Proteins

Some Optical Properties of S-β-(4-Pyridylethyl)-L-Cysteine and its Wheat Gluten and Serum Albumin Derivatives

1971 ◽  
Vol 49 (9) ◽  
pp. 1042-1049 ◽  
Author(s):  
Y. Victor Wu ◽  
James E. Cluskey ◽  
L. H. Krull ◽  
Mendel Friedman
Keyword(s):  
Optical Properties ◽  
Ionic Strength ◽  
Serum Albumin ◽  
Disulfide Bonds ◽  
Wheat Gluten ◽  
Spectrophotometric Titration ◽  
Optical Rotatory ◽  
Pyridyl Group ◽  
Helical Content ◽  
Α Helix

The optical properties of S-β-(4-pyridylethyl)-L-cysteine (PEC) and its bovine serum albumin (BSA) and wheat gluten derivatives were studied in 0.01–0.1 N HCl. Optical rotatory dispersions (O.R.D.), circular dichroism (C.D.), ultraviolet (U.V.), and infrared (I.R.) spectra were obtained of PEC, BSA, BSA reduced with mercaptoethanol and alkylated with 4-vinylpyridine (PE-BSA), BSA reduced with mercaptoethanol and alkylated with acrylonitrile (CN-BSA), gluten, gluten reduced with mercaptoethanol and alkylated with 4-vinylpyridine (PE-gluten), and gluten reduced with mercaptoethanol and alkylated with acrylonitrile (CN-gluten). I.R. spectra of the proteins showed the presence of α-helical and unordered conformations. The U.V. absorption at 254 mμ of PEC and PE-BSA depends on pH; a pK value near 6 for the pyridyl group was obtained by spectrophotometric titration. The possible use of PEC as a conformation probe was explored. The O.R.D. of PEC depends on concentration, solvent, and pH but not on ionic strength. The O.R.D. data of proteins were analyzed by the Moffitt–Yang method to get α-helical contents. These helical contents indicate that there is not enough interaction left to support α-helix in gluten with disulfide bonds broken at pH 2.2. However, approximately one-third of the helical content of BSA persists without the aid of disulfide bonds.

A model to explain the osmotic pressure behavior of hemoglobin and serum albumin

1990 ◽  
Vol 68 (5) ◽  
pp. 894-898 ◽  
Author(s):  
Ivan L. Cameron ◽  
Gary D. Fullerton
Keyword(s):  
Serum Albumin ◽  
Osmotic Pressure ◽  
Protein Conformation ◽  
Protein A ◽  
Dry Mass ◽  
Globular Proteins ◽  
Pressure Data ◽  
Water Of Hydration ◽  
Pressure Water ◽  
Solvent Volume

Previously published osmotic pressure data on hemoglobin and bovine serum albumin were used to determine the osmotically unresponsive solvent volume per unit dry mass of protein. A model is presented that accounts for the osmotic pressure of globular proteins based on a surface-associated osmotically unresponsive solvent volume. The model also accounts for changes in the osmotically unresponsive solvent volume owing to changes in pH, cosolute salt concentration, protein conformation, and protein aggregation.Key words: hemoglobin, serum albumin, osmotic pressure, water of hydration, salt, pH, model of protein structure.

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