Guanidine hydrochloride and acid denaturation of horse, cow, and Candida krusei cytochromes c

Biochemistry ◽  
1974 ◽  
Vol 13 (6) ◽  
pp. 1289-1294 ◽  
Author(s):  
J. A. Knapp ◽  
C. N. Pace
1967 ◽  
Vol 62 (1) ◽  
pp. 99-104 ◽  
Author(s):  
KOZO HAMAGUCHI ◽  
KIYOSHI IKEDA ◽  
HIROKO SAKAI ◽  
KOICHI SUGENO ◽  
KOZO NARITA

1983 ◽  
Vol 213 (3) ◽  
pp. 687-700 ◽  
Author(s):  
M N Robinson ◽  
A P Boswell ◽  
Z X Huang ◽  
C G S Eley ◽  
G R Moore

1H-n.m.r. studies of horse, tuna, Candida krusei and Saccharomyces cerevisiae cytochromes c showed that each of the proteins contains a similar cluster of residues at the bottom of the protein that assists in shielding the haem from the solvent. The relative positions of the residues forming these clusters vary continuously with temperature, and they change with the change in protein redox state. This conformational heterogeneity is discussed with reference to the conformational flexibility of cytochrome c around residues 57, 59 and 74. Spectroscopic measurements of pKa values for Lys-55 (horse and tuna cytochromes c) and His-33 and His-39 (C. krusei and S. cerevisiae cytochromes c) are in excellent agreement with expectations based on chemical-modification studies of horse cytochrome c. [Bosshard & Zürrer (1980) J. Biol. Chem. 255, 6694-6699] and on the X-ray-crystallographic structure of tuna cytochrome c [Takano & Dickerson (1981) J. Mol. Biol. 153, 79-94, 95-115].


1978 ◽  
Vol 39 (01) ◽  
pp. 193-200 ◽  
Author(s):  
Erwin F Workman ◽  
Roger L Lundblad

SummaryAn improved method for the preparation of bovine α-thrombin is described. The procedure involves the activation of partially purified prothrombin with tissue thromboplastin followed by chromatography on Sulfopropyl-Sephadex C-50. The purified enzyme is homogeneous on polyacrylamide discontinuous gel electrophoresis and has a specific activity toward fibrinogen of 2,200–2,700 N.I.H. U/mg. Its stability on storage in liquid media is dependent on both ionic strenght and temperature. Increasing ionic strength and decreasing temperature result in optimal stability. The denaturation of α-thrombin by guanidine hydrochloride was found to be a partially reversible process with the renatured species possessing properties similar to “aged” thrombin. In addition, the catalytic properties of a-thrombin covalently attached to agarose gel beads were also examined. The activity of the immobilized enzyme toward fibrinogen was affected to a much greater extent than was the hydrolysis of low molecular weight, synthetic substrates.


2018 ◽  
Vol 11 (2) ◽  
pp. 164-172
Author(s):  
О.A. Yessimova ◽  
◽  
А.О. Adilbekova ◽  
M.Zh. Kerimkulova ◽  
G.D. Isenova ◽  
...  

2019 ◽  
Vol 16 (2) ◽  
pp. 309-313
Author(s):  
Mustafa Kemal Gümüş

Aim and Objective: In this work, water was used as solvent for the eco-friendly synthesis of imines under microwave irradiation. In the first step of the study, 5-pyridinyl-3-amino-1,2,4-triazole hydrochlorides were synthesized in the reaction of amino guanidine hydrochloride with different pyridine carboxylic acids under acid catalysis. A green method for 5-pyridinyl-3-amino-1,2,4-triazoles was developed with the assistance of microwave synthesis. In the second step, the eco-friendly synthesis of imines was achieved by reacting 5- pyridinyl-2H-1,2,4-triazol-3-amine hydrochlorides with salicylic aldehyde derivatives to produce 2-(5- pyridinyl-2H-1,2,4-triazol-3-ylimino)methyl)phenol imines. Materials and Methods: Microwave experiments were done using a monomode Anton Paar Monowave 300 microwave reactor (2.45 GHz). Reaction temperatures were monitored by an IR sensor. Microwave experiments were carried out in sealed microwave process vials G10 with maximum reaction volume of 10 mL. Results: When alternative methods were used, it was impossible to obtain good yields from ethanol. Nevertheless, the use of water was successful for this reaction. After 1-h microwave irritation, a yellow solid was obtained in 82% yield. Conclusion: In this work an eco-friendly protocol for the synthesis of Schiff bases from 5-(pyridin-2-, 3- or 4- yl)-3-amino-1,2,4-triazoles and substituted salicylic aldehydes in water under microwave irradiation was developed. Under the found conditions the high yields for the products were achieved at short reaction time and with an easy isolation procedure.


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