An N.M.R. study of the helix-coil transition in CNBr fragments of collagen

1975 ◽  
Vol 28 (1) ◽  
pp. 41 ◽  
Author(s):  
BD Batts ◽  
RA Brown ◽  
P Mason ◽  
AR Ward
Keyword(s):  
Molecular Weight ◽  
High Resolution ◽  
Optical Rotation ◽  
Thermal Transitions ◽  
Coil Transition

Thermal transitions in solutions of collagen and two of its fragments α1CB3 (13600 molecular weight) and α1CB2 (3600) have been examined by high-resolution proton n.m.r. spectroscopy and by optical rotation.

scholarly journals Studies on silk proteins I. The properties and constitution of fibroin. The conversion of fibroin into a water-soluble form and its bearing on the phenomenon of denaturation

1947 ◽  
Vol 190 (1021) ◽  
pp. 145-169 ◽  
Keyword(s):  
Molecular Weight ◽  
Soluble Protein ◽  
Optical Rotation ◽  
Amino Nitrogen ◽  
Water Soluble ◽  
Soluble Form ◽  
Secondary Process ◽  
Amide Nitrogen ◽  
Water Soluble Protein ◽  
The Mean

Some of the constituent amino-acids of fibroin (degummed silk) are determined. Special attention is directed to histidine, owing to its use in the calculation of the molecular weight of fibroin. A value of 0⋅45% has been found by methods in which the histidine is isolated as nitranilate or di-(3:4-dichlorobenzenesulphonate). Other values obtained are serine 12⋅6%, threonine 1⋅5%, tyrosine 10⋅6%, and proline 1⋅5%. Hydroxyproline appears to be absent, but the presence of small amounts of some hydroxyamino-acid other than serine and threonine is indicated. The mean residue weight of fibroin is determined by three methods, one of which is a new method based on analysis of the complex formed between fibroin and cupri-ethylenediamine. This method gives a Cu:fibroin-N ratio of 1:1⋅92 and, if allowance is made for co-ordination with the tyrosine hydroxy1 group, an equivalence of 1⋅964 atoms of peptide-nitrogen to 1 atom of copper is obtained. The three methods give an average value of 78⋅0 for the mean residue weight of fibroin. This value, together with the most acceptable data for amino-acid constituents, indicate that the unidentified anhydro-residues (about 20%) have a mean residue weight of about 107. Evidence is presented that fibroin contains no amide-nitrogen. Methods for the determination of amide-nitrogen at present in use, which indicate a content of 1 to 2%, are considered to be unreliable. Fibroin dissolved in cupri-ethylenediamine gives, on neutralization and dialysis of the resulting solution, a water-soluble protein. The production of this water-soluble protein is attended by little or no degradation of the original fibroin as shown by determinations of fluidity, amino-nitrogen, and acid- and alkali-combining power. The water-soluble protein is precipitated by the normal protein-precipitating reagents, but in every instance examined the precipitated material exhibits an insolubility comparable with that of the original fibroin. Factors responsible for the solubilization process are investigated and data for molecular weight, titration values, ultra-violet absorption spectra, reducing activity, optical rotation, tryptic hydrolysis, and viscosity for both soluble and dispersed fibroin are given. Soluble fibroin has [ α ] D 15 — 53⋅1° and dispersed fibroin [ α ] D 15 — 58⋅9°, both in aqueous media. The preparation and properties of films and filaments of fibroin are described. Films of fibroin can be prepared that are water-soluble. On stretching, these films show strain-birefringence, acquire considerable tensile strength, and become insoluble in water, but X-ray examination gives the β -keratin pattern for both the stretched and unstretched films. Reasons are advanced for considering the water-soluble form of fibroin to be the native or renatured protein and the original protein to be the denatured form. The denaturation of fibroin is discussed on the basis that denaturation is essentially an unfolding of a coiled long-chain molecule. The subsequent aggregation of the uncoiled molecules to give an insoluble product is considered to be a secondary process. Some aspects of protein and polypeptide chains as macro-molecules are also discussed.

MSAllstrategy for comprehensive quantitative analysis of PEGylated-doxorubicin, PEG and doxorubicin by LC-high resolution q-q-TOF mass spectrometry coupled with all window acquisition of all fragment ion spectra

The Analyst ◽  
2017 ◽  
Vol 142 (22) ◽  
pp. 4279-4288 ◽  
Author(s):  
Lei Yin ◽  
Chong Su ◽  
Tianming Ren ◽  
Xiangjun Meng ◽  
Meiyun Shi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Molecular Weight ◽  
Quantitative Analysis ◽  
High Resolution ◽  
Covalent Attachment ◽  
Small Molecular Weight ◽  
Biological Efficacy ◽  
Therapeutic Compounds

Covalent attachment of PEG to therapeutic compounds (PEGylation) is one of the best techniques to improve the biological efficacy of small molecular weight drugs.

High Resolution Electron Beam Negative Resist with Very Narrow Molecular Weight Distributions

1982 ◽  
Vol 129 (3) ◽  
pp. 663-665 ◽  
Author(s):  
Kingo Itaya ◽  
Kimio Shibayama ◽  
Teruo Fujimoto
Keyword(s):  
Molecular Weight ◽  
Electron Beam ◽  
High Resolution ◽  
Molecular Weight Distributions ◽  
Resolution Electron ◽  
Weight Distributions

The specific capsular polysaccharide of Streptococcus pneumoniae type 15A (American type 30)

1984 ◽  
Vol 62 (2-3) ◽  
pp. 151-161 ◽  
Author(s):  
Martine Caroff ◽  
Malcolm B. Perry
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Streptococcus Pneumoniae ◽  
Magnetic Resonance ◽  
High Molecular Weight ◽  
Capsular Polysaccharide ◽  
Optical Rotation ◽  
Periodate Oxidation ◽  
Magnetic Resonance Studies ◽  
Structure Formula

The specific capsular polysaccharide of Streptococcus pneumoniae type 15A (American type 30) is composed of D-galactose (three parts), D-glucose (one part), 2-acetamido-2-deoxy-D-glucose (one part), phosphate (one part), and glycerol (one part). Hydrolysis, periodate oxidation, methylation, optical rotation, and nuclear magnetic resonance studies showed that the polysaccharide is a high molecular weight linear polymer of a pentasaccharide repeating unit having the structure:[Formula: see text]

The structures of the two lipopolysaccharide O-chains produced by Salmonella boecker

1988 ◽  
Vol 66 (10) ◽  
pp. 1066-1077 ◽  
Author(s):  
Jean-Robert Brisson ◽  
Malcolm B. Perry
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
High Molecular Weight ◽  
Nitrous Acid ◽  
Optical Rotation ◽  
Partial Hydrolysis ◽  
Magnetic Resonance Studies ◽  
High Molecular Weight Polymers ◽  
Nuclear Magnetic

Salmonella boecker, which belongs to group 0:6, 14(H) and shows the antigenic factors 6, 14, [1], and [25], defined by the Kauffmann–White system, produces two lipopolysaccharides differing from each other in the structures of their 0-polysaccharide moieties. By glycose composition, partial hydrolysis, nitrous acid deamination, methylation, optical rotation, and 1H and 13C nuclear magnetic resonance studies, the O-polysaccharides were demonstrated to be high-molecular-weight polymers (I and II) composed of either structurally related repeating tetrasaccharide or repeating pentasaccharide units having the structuresand[Formula: see text][Formula: see text]

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