Effect of Maleylation and Amidination of Hemoglobin on its Haptoglobin and Oxygen Reactions

1971 ◽  
Vol 49 (2) ◽  
pp. 148-153 ◽  
Author(s):  
W. L. Lockhart ◽  
David B. Smith
Keyword(s):  
Maleic Anhydride ◽  
Sedimentation Rate ◽  
Gel Filtration ◽  
Bohr Effect ◽  
Human Hemoglobin ◽  
Amino Groups ◽  
Structural Alterations ◽  
Cooperative Effects ◽  
Oxygen Equilibrium

Maleic anhydride and ethyl acetimidate reacted readily with all ε-amino groups of human hemoglobin. Maleyl-hemoglobin showed evidence of structural alterations and did not bind to haptoglobin. Amidino-hemoglobin was similar to hemoglobin in electrophoresis below pH 9, sedimentation rate, and gel filtration. Its oxygen equilibrium showed no cooperative effects or Bohr effect. Since it retained capacity to bind haptoglobin, it is concluded that hemoglobin amino groups are not involved in the reaction with haptoglobin.

scholarly journals Chloride ion independence of the Bohr effect in a mutant human hemoglobin beta (V1M+H2deleted).

1994 ◽  
Vol 269 (39) ◽  
pp. 23965-23969
Author(s):  
C. Fronticelli ◽  
I. Pechik ◽  
W.S. Brinigar ◽  
J. Kowalczyk ◽  
G.L. Gilliland
Keyword(s):  
Chloride Ion ◽  
Bohr Effect ◽  
Human Hemoglobin

Bohr effect of human hemoglobin A: Magnitude of negative contributions determined by the equilibrium between two tertiary structures

2014 ◽  
Vol 190-191 ◽  
pp. 41-49 ◽  
Author(s):  
Kehinde O. Okonjo ◽  
Abimbola M. Olatunde ◽  
Adedayo A. Fodeke ◽  
J. Oyebamiji Babalola
Keyword(s):  
Bohr Effect ◽  
Human Hemoglobin ◽  
Tertiary Structures ◽  
Hemoglobin A

scholarly journals Sericin cocoon bio-compatibilizer for reactive blending of thermoplastic cassava starch

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thanongsak Chaiyaso ◽  
Pornchai Rachtanapun ◽  
Nanthicha Thajai ◽  
Krittameth Kiattipornpithak ◽  
Pensak Jantrawut ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Maleic Anhydride ◽  
Crystal Size ◽  
Thermoplastic Starch ◽  
Cassava Starch ◽  
Chain Extension ◽  
Amino Groups ◽  
Reactive Blending ◽  
Elongation At Break ◽  
Small Crystal Size

AbstractCassava starch was blended with glycerol to prepare thermoplastic starch (TPS). Thermoplastic starch was premixed with sericin (TPSS) by solution mixing and then melt-blended with polyethylene grafted maleic anhydride (PEMAH). The effect of sericin on the mechanical properties, morphology, thermal properties, rheology, and reaction mechanism was investigated. The tensile strength and elongation at break of the TPSS10/PEMAH blend were improved to 12.2 MPa and 100.4%, respectively. The TPS/PEMAH morphology presented polyethylene grafted maleic anhydride particles (2 μm) dispersed in the thermoplastic starch matrix, which decreased in size to approximately 200 nm when 5% sericin was used. The melting temperature of polyethylene grafted maleic anhydride (121 °C) decreased to 111 °C because of the small crystal size of the polyethylene grafted maleic anhydride phase. The viscosity of TPS/PEMAH increased with increasing sericin content because of the chain extension. Fourier-transform infrared spectroscopy confirmed the reaction between the amino groups of sericin and the maleic anhydride groups of polyethylene grafted maleic anhydride. This reaction reduced the interfacial tension between thermoplastic starch and polyethylene grafted maleic anhydride, which improved the compatibility, mechanical properties, and morphology of the blend.

scholarly journals THE EFFECT OF FORMALDEHYDE ON THE OXYGEN EQUILIBRIUM OF HEMOGLOBIN

1954 ◽  
Vol 37 (6) ◽  
pp. 775-780 ◽  
Author(s):  
Karl F. Guthe
Keyword(s):  
Oxygen Pressure ◽  
Oxygen Affinity ◽  
Sulfhydryl Groups ◽  
Human Hemoglobin ◽  
Hill’S Equation ◽  
Oxygen Equilibrium ◽  
Hill's Equation ◽  
Hemoglobin Molecule

1. When formaldehyde (0.10 M) is added to solutions of human hemoglobin, the oxygen affinity of the hemoglobin increases considerably (more than tenfold near pH 7). The interaction between hemes of the same hemoglobin molecule decreases, as shown by a drop in the value of n in Hill's equation from 2.9 to 1.5 or less. 2. In the presence of formaldehyde, both n and the oxygen pressure for half-saturation fall gradually as the pH rises in the range from pH 6.2 to 7.2. 3. Some of the effect of formaldehyde on the oxygen equilibrium may be due to combination with sulfhydryl groups of the protein, but nitrogenous groups are probably also involved.

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