scholarly journals The Structure of Surface-Denatured Protein. IV. The Molecular Weight, Surface Area and Shape of the Surface-Denatured Hemoglobin Molecule

1952 ◽  
Vol 25 (2) ◽  
pp. 121-123 ◽  
Author(s):  
Kazutomo Imahori
Keyword(s):  
Molecular Weight ◽  
Surface Area ◽  
Denatured Protein ◽  
Hemoglobin Molecule

scholarly journals CONCENTRATION AND PURIFICATION OF BACTERIOPHAGE

1938 ◽  
Vol 21 (3) ◽  
pp. 335-366 ◽  
Author(s):  
John H. Northrop
Keyword(s):  
Molecular Weight ◽  
Small Molecules ◽  
Specific Activity ◽  
Active Agent ◽  
Pure Substance ◽  
Solubility Curve ◽  
Denatured Protein ◽  
Sedimentation Constant ◽  
Rate Of Sedimentation ◽  
Living Organisms

1. A method for isolating a nucleoprotein from lysed staphylococci culture is described. 2. It is homogeneous in the ultracentrifuge and has a sedimentation constant of 650 x 10–13 cm. dyne–1 sec.–1, corresponding to a molecular weight of about 300,000,000. 3. The diffusion coefficient varies from about 0.001 cm.2/day in solutions containing more than 0.1 mg. protein/ml. to 0.02 in solutions containing less than 0.001 mg. protein/ml. The rate of sedimentation also decreases as the concentration decreases. It is suggested, therefore, that this protein exists in various sized molecules of from 500,000–300,000,000 molecular weight, the proportion of small molecules increasing as the concentration decreases. 4. This protein is very unstable and is denatured by acidity greater than pH 5.0, by temperature over 50°C. for 5 minutes. It is digested by chymo-trypsin but not by trypsin. 5. The loss in activity by heat, acid, and chymo-trypsin digestion is roughly proportional to the amount of denatured protein formed under these conditions. 6. The rate of diffusion of the protein is the same as that of the active agent. 7. The rate of sedimentation of the protein is the same as that of the active agent. 8. The loss in activity when susceptible living or dead bacteria are added to a solution of the protein is proportional to the loss in protein from the solution. Non-susceptible bacteria remove neither protein nor activity. 9. The relative ultraviolet light absorption, as determined directly, agrees with that calculated from Gates' inactivation experiments in the range of 2500–3000 Å. u. but is somewhat greater in the range of 2000–2500 Å. u. 10. Solubility determinations showed that most of the preparations contained at least two proteins, one being probably the denatured form of the other. Two preparations were obtained, however, which had about twice the specific activity of the earlier ones and which gave a solubility curve approximating that of a pure substance. 11. It is suggested that the formation of phage may be more simply explained by analogy with the autocatalytic formation of pepsin and trypsin than by analogy with the far more complicated system of living organisms.

Mechanical Properties of Blends of Crystallizable Polybutadienes Containing Amorphous Polybutadiene Diblock Copolymers

1994 ◽  
Vol 67 (2) ◽  
pp. 342-347
Author(s):  
Moira Marx Nir ◽  
Robert E. Cohen
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Surface Area ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Tensile Failure ◽  
Interfacial Surface ◽  
Failure Properties ◽  
Enhanced Properties

Abstract Tensile failure properties of syndiotactic 1,2 polybutadiene/trans 1,4 polybutadiene crystalline blends are improved by addition of 5–10% amorphous 1,2 polybutadiene/1,4 polybutadiene diblock copolymer. The effect of block molecular weight and microphase behavior of the diblock copolymer was investigated. Heterogeneous diblocks enhance blend properties to a greater extent than homogeneous diblocks. In blends with enhanced properties, percent coverage of interfacial surface area by diblock is on the order of 10%.

scholarly journals A METHOD FOR THE DETERMINATION OF DIFFUSION CONSTANTS AND THE CALCULATION OF THE RADIUS AND WEIGHT OF THE HEMOGLOBIN MOLECULE

1929 ◽  
Vol 12 (4) ◽  
pp. 543-554 ◽  
Author(s):  
John H. Northrop ◽  
M. L. Anson
Keyword(s):  
Molecular Weight ◽  
Carbon Monoxide ◽  
Diffusion Coefficient ◽  
Porous Membrane ◽  
Diffusion Constants ◽  
Einstein's Equation ◽  
Hemoglobin Molecule

A method is described for determining the diffusion coefficient of solutes by determining the rate of passage of the solute through a thin porous membrane between two solutions of different concentration. The method has been used to determine the diffusion coefficient of carbon monoxide hemoglobin. This was found to be 0.0420 ± 0.0005 cm.2 per day at 5°C. The molecular weight of carbon monoxide hemoglobin calculated by means of Einstein's equation from this quantity is 68,600 ± 1,000.

Mixing of Carbon Black with Rubber. VI. Analysis of NR/SBR Blends

1988 ◽  
Vol 61 (4) ◽  
pp. 609-618 ◽  
Author(s):  
George R. Cotten ◽  
Lawrence J. Murphy
Keyword(s):  
Molecular Weight ◽  
Carbon Black ◽  
High Molecular Weight ◽  
Surface Area ◽  
Bound Rubber ◽  
Very High

Abstract The distribution of carbon black in NR/SBR blends was determined through the analysis of bound rubber. The NR/SBR blends were found to be very different from the previously studied SBR/BR compounds: these differences were assigned to mutual insolubility of the two polymers and a very high molecular weight of NR. In NR/SBR blends, it was found that changes in molecular weight of the polymer has no effect on the carbon black distribution in the blend. While the “activity” of carbon black did not affect the distribution, the loading of the black in NR decreased linearly with increasing surface area of the black. Approximately 35% of normal tread blacks (surface area 80–100 m2/g) was found in the NR phase. However, the bond between NR and carbon black is quite weak, and black continues to migrate into the SBR phase on prolonged mixing or during blending of NR and SBR masterbatches.

Effect of variations of CuIIX2/L, surface area of Cu0, solvent, and temperature on atom transfer radical polyaddition of 4-vinylbenzyl 2-bromo-2-isobutyrate inimers

RSC Advances ◽  
2016 ◽  
Vol 6 (57) ◽  
pp. 51816-51822 ◽  
Author(s):  
Chih-Feng Huang ◽  
Shiao-Wei Kuo ◽  
Daniela Moravčíková ◽  
Jyun-Ci Liao ◽  
Yu-Min Han ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Surface Area ◽  
Atom Transfer ◽  
Catalytic Systems

Optimization of atom transfer radical polyadditions using commercially available catalytic systems allowed obtaining control over the polyester architecture and functionality and functional linear polyesters with high molecular weight (Mw = 16 200).

scholarly journals Use of nanoadvanced activated carbon, alumina and ferric adsorbents for humics removal from water: isotherm study

2020 ◽  
Vol 3 (6) ◽  
pp. 841-856
Author(s):  
Cecile Andre Stanford ◽  
Majeda Khraisheh ◽  
Fares Al Momani ◽  
Ahmad B. Albadarin ◽  
Gavin M. Walker ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Activated Carbon ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Water Hardness ◽  
Freundlich Isotherm ◽  
Lower Surface ◽  
Activated Alumina ◽  
Isotherm Study ◽  
Beta Form

AbstractThe adsorption of humic substances on three different adsorbents was investigated and adsorption isotherms were applied in this research. The three adsorbents studied include granular activated carbon (GAC), ferric oxihydroxide in its beta form (β-FeOOH) and iron-coated activated alumina (AAFS). Physical and chemical characteristics of the adsorbents were also fully investigated. Calcium was added to the HS solution in order to represent water with a hardness equivalent to water hardness typically found in London (UK). The examination of the GAC indicated a large microporous area with lower surface area associated with meso- and macropores. The AAFS and β-FeOOH did not present any microporous area. The overall surface area was high for GAC (980 m2 g−1) but lower for AAFS (286 m2 g−1) and β-FeOOH (360 m2 g−1). The Freundlich isotherm model was fitted to all adsorbent–adsorbate systems. It was shown that GAC offered a large adsorption capacity for removal of low molecular weight humics F1 (MW 0–5 kDa) but not for substances with molecular weight larger than 10 kDa (F3). The β-FeOOH adsorption capacity was only 0.43 mg g−1, compared with 9.11 and 2.55 mg g−1 on GAC and AAFS, respectively. On the contrary, F1 is not well adsorbed and only F2 (5–10 kDa) can be efficiently removed by AAFS and β-FeOOH. It was strongly suggested that precipitation/condensation occurred on the adsorbent surface.

Use of blue dextran for measuring changes in perfused vascular surface area in lungs

1992 ◽  
Vol 262 (3) ◽  
pp. H728-H733
Author(s):  
D. L. Roerig ◽  
C. A. Dawson ◽  
S. B. Ahlf ◽  
R. D. Bongard ◽  
J. H. Linehan ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Serum Albumin ◽  
Surface Area ◽  
Airway Pressure ◽  
Average Molecular Weight ◽  
Low Flow ◽  
Blue Dye ◽  
Reactive Blue 2 ◽  
Blue Dextran ◽  
Vascular Surface

We investigated the uptake and efflux of Blue Dextran in the isolated perfused rabbit lung. Blue Dextran is a high-molecular-weight glucose polymer (original mol wt 2 x 10(6) g/mol) containing covalently bonded Reactive Blue 2 dye (approximately mmol/g dextran). This blue dye is known for its high binding affinity to a wide variety of proteins, with a particularly high affinity for serum albumin. In isolated rabbit lungs perfused with a protein-free perfusate, both bolus injection and recirculation of Blue Dextran revealed a rapid saturable uptake. Once the lungs were loaded with Blue Dextran, efflux of the Blue Dextran accumulated in the lungs could be induced by addition of bovine serum albumin (BSA) to the recirculating perfusate. The amount of BSA-induced efflux of Blue Dextran from the lung was independent of perfusate flow. When the left pulmonary artery was ligated after the lungs had been loaded with Blue Dextran, the dye-induced BSA efflux was only about 50% of normal. Release of the ligature so that both lungs were perfused resulted in efflux of the remaining Blue Dextran. The combination of high airway pressure and low flow also reduced the dye efflux, and the effect was reversed by reducing the airway pressure. With the assumption that the high average molecular weight of Blue Dextran confines this molecule to interaction with proteins on the vascular surface, the results of this study suggest that Blue Dextran uptake and its BSA-induced efflux are proportional to the perfused vascular surface area in the lung.

Irreversible heat denaturation of bovine α-lactalbumin

1986 ◽  
Vol 53 (2) ◽  
pp. 249-258 ◽  
Author(s):  
Lesley C. Chaplin ◽  
Richard L. J. Lyster
Keyword(s):  
Molecular Weight ◽  
Sodium Dodecyl Sulphate ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Heat Denaturation ◽  
Two Dimensional ◽  
Native Protein ◽  
Denatured Protein ◽  
Hydrolysis Of

SUMMARYThe irreversible heat denaturation of α-lactalbumin (α-la) in 0·1 M-phosphate, pH 7·0, at 100 °C was studied using polyacrylamide-gel electrophoresis (PAGE). PAGE revealed two groups of bands, one moving faster than native α-la and one slower, in addition to some denatured protein which remained at the origin and some residual native α-la. The faster group had unchanged molecular weight, but an increase in charge, partly due to hydrolysis of glutamine and asparagine residues. The slower group was shown by two-dimensional sodium dodecyl sulphate-PAGE to be oligomers of denatured α-la; formation of the smaller oligomers preceded the larger ones. The oligomers reverted to monomers in the presence of dithiothreitol, showing that they were disulphide-linked aggregates of denatured α-la. Immuno-blots of the gels showed that both fast and slow groups of bands had irreversibly lost most of the antigenicity of the native protein.

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