A comparison of the conformational stabilities of homologous hemoproteins

Immunological measurements of conformational motility in regions of the myoglobin molecule

“…The standard free energy of unfolding for this region must be at least -8.7 kcal mol-1-a value considerably more negative than those for the N-terminal (1-55) and C-terminal (132-153) regions which were -3.9 and -3.3 kcal mol-1 at 295 and 298 K, respectively. The overall AG°for the unfolding of myoglobin is estimated to be -13.6 kcal mol-1 at 298 K (Puett et al, 1973). Such values no doubt relate to the most tightly folded regions of the molecule and Kca"f values for such regions would not be accessible using the present methods.…”

Light-scattering investigations of the subunit dissociation of human hemoglobin A. Effects of various neutral salts

“…Most of the salts of the Hofmeister series are relatively in-effective denaturing agents when compared to the effects of such reagents as urea or Gdn-HCl (Noelken, 1970;Puett et al, 1973;Harrington and Herskovits, 1975;Pace, 1975). Absorbance and ORD measurements on CO-hemoglobin solutions in the presence of 0 to 4 M NaCl have shown no significant changes in the molar extinction coefficient, cm, at the 418-nm Soret region and in the mean residue rotation, [m']x, of the conformationally sensitive peptide-absorbing region at 233 nm.…”

Reduced stability and accelerated autoxidation of tuna myoglobin in association with freezing and thawing

“…Determination of Free Energy for Unfolding. To both unfrozen and frozen/thawed Mb solutions was added an equal volume of 0.5-6 M Gdn-HCl, which was previously adjusted to respective pH values (Puett et al, 1973). These solutions were allowed to stand at 4 °C for 20 h and subsequently incubated in a water bath at 20 °C for 2 h. Their Soret absorbances at 409 nm were recorded at due time intervals as a parameter of denaturation.…”