scholarly journals The crystalline yolk-platelet proteins and their soluble plasma precursor in an amphibian, Xenopus laevis

1971 ◽  
Vol 124 (4) ◽  
pp. 759-766 ◽  
Author(s):  
M. R. Redshaw ◽  
B. K. Follett
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Xenopus Laevis ◽  
Amino Acid Composition ◽  
High Molecular Weight ◽  
Molecular Rearrangement ◽  
Yolk Proteins ◽  
Platelet Protein ◽  
Yolk Platelet ◽  
Preparative Ultracentrifugation

A single lipophosphoprotein complex, vitellogenin, was isolated and purified from the plasma of oestrogen-stimulated female toads by preparative ultracentrifugation and chromatography on TEAE-cellulose (triethylaminoethylcellulose). The protein contains 12% lipid, 1.5% phosphorus, 1.6% calcium and smaller amounts of carbohydrates and biliverdin. In amino acid composition it is identical with total yolk-platelet protein. The platelet protein, however, is fractionated on TEAE-cellulose into two components, a high-molecular-weight lipovitellin and a smaller phosvitin. Analyses of the soluble plasma vitellogenin suggest that it is a complex of two phosvitin molecules covalently bound to one lipovitellin dimer, and that it is the immediate precursor of the yolk proteins, into which it is converted by a molecular rearrangement. Uptake of vitellogenin from the plasma into the growing oocyte, and its subsequent crystallization as a yolk platelet, appear to be enhanced by gonadotrophic hormones.

The isolation and properties of 1·6 S γ -histone from calf thymocytes

1958 ◽  
Vol 149 (934) ◽  
pp. 36-41 ◽  
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Physicochemical Properties ◽  
Amino Acid Composition ◽  
High Molecular Weight ◽  
Acid Composition ◽  
The Other ◽  
Amino Acid Compositions

The isolation of 1·6 S γ -histone is described, its amino-acid composition recorded and an account given of some of its physicochemical properties. Its molecular weight has been calculated from sedimentation velocities to be 74000 in its unaggregated condition. It thus represents a second histone of high molecular weight present in the nuclei of calf thymocytes. Both β and 1·6 S γ -histone are distinguished from the other four components in their ability to undergo aggregation. The γ -histone, however, does not aggregate so readily or so extensively as does β -histone. These two histones are also clearly distinguished by their amino-acid compositions.

scholarly journals SCIENTIFIC SUBSTANTIATION OF PHYSICAL PROPERTIES OF FISH GELATIN

2018 ◽  
pp. 132-140
Author(s):  
Adelia Adlerovna Bekesheva ◽  
Olesya Sergeevna Yakubova
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Physical Properties ◽  
Amino Acid Composition ◽  
High Molecular Weight ◽  
Melting Temperature ◽  
Weight Distribution ◽  
Dynamic Viscosity ◽  
Fish Gelatin ◽  
Molecular Weight Fractions

The article presents the advantages of fish gelatin available for nutritional purposes in comparison with gelatin of mammals. Factors forming the basic physical properties of gelatin as a structure-forming agent have been identified. The analysis of melting temperature of jelly and the dynamic viscosity of fish gelatin solutions has been carried out. The melting temperature of jelly prepared from fish gelatin is 4°C lower than the minimum normalized value for mammalian gelatin, which is stipulated by the specific features of their amino acid composition. There has been found an increased value of the parameter “dynamic viscosity” (on average 30 mPa·s) in comparison with the standard value of gelatin of animal origin (on average 23 mPa·s). The molecular weight composition of fish gelatin has been determined. Gelatin has been stated not an individual substance, but a multiphase system consisting of a mixture of linear polypeptides and their aggregates. In the molecular weight distribution of fish gelatin 81.7% falls to a high molecular weight fraction with a mass higher than 100 kDa. Compared with gelatin obtained from the skins of cattle fish gelatin has higher content (by 34.7%) of molecular weight fractions (β- and γ-chains) and lower content (by 36.2%) of α-chains. The predominance of high molecular weight fractions in the composition of fish gelatin causes high rates of dynamic viscosity of its solutions. It was established that the interval of temperature transition ‘fibril-globule’ in fish gelatin is 20-25°C, and in animal gelatin - 28-30°C. It has been inferred that the thermal dependences of the rheological properties of fish and animal gelatin are different. It has been substantiated that collagens of different origin give gelatin with different properties. Physical properties of fish gelatin depend on the amino acid composition of a gelatin molecule, which is determined by the nature of collagen, and on the molecular weight distribution of α-, β-, γ-fractions of gelatin, which is determined by technological factors of gelatin production.

The utilization of yolk platelets by tissues of Xenopus embryos studied by a safranin staining method

Development ◽  
1965 ◽  
Vol 14 (2) ◽  
pp. 191-212
Author(s):  
G. G. Selman ◽  
G. J. Pawsey
Keyword(s):  
Electron Microscopy ◽  
Amino Acid ◽  
Chemical Analysis ◽  
Amino Acid Composition ◽  
Rana Pipiens ◽  
Staining Method ◽  
Peripheral Zone ◽  
Main Body ◽  
Yolk Platelet ◽  
Similar Amino Acid

The amphibian yolk platelet is a particular kind of food-reserve granule which may be easily recognized by microscopy and which is abundant in the cytoplasm of amphibian eggs and embryos. Wallace & Karasaki (1963) developed a method by which intact yolk platelets were isolated from eggs of Rana pipiens and were shown by electron microscopy to be practically free from other materials. Chemical analysis of such yolk platelets by Wallace (1963a, b) showed that the crystalline main body is made up of two components, a phosphoprotein of similar amino-acid composition to avian phosvitin and a lipoprotein similar to avian α-lipovitellin, the molecular proportions being 2 to 1 respectively. Surrounding this crystalline main body of the yolk platelet there is a granular peripheral zone which has been reported to contain both protein resembling histone (Horn, 1962) and polysaccharide (Ohno, Karasaki & Takata, 1964).

scholarly journals Platelet protein organization: analysis by treatment with membrane- permeable cross-linking reagents

Blood ◽  
1982 ◽  
Vol 59 (3) ◽  
pp. 502-513 ◽  
Author(s):  
GE Davies ◽  
J Palek
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Polyacrylamide Gel Electrophoresis ◽  
Cytoskeletal Proteins ◽  
Cross Linking ◽  
Membrane Glycoproteins ◽  
Platelet Protein ◽  
High Molecular Weight Material ◽  
Organization Analysis ◽  
Thrombin Activation

Abstract We have examined platelet protein organization by treatment of intact resting or thrombin-activated platelets with two cross-linking reagents, diamide or dithiobis(succinimidyl propionate) (DTSP). Cross- linked complexes were separated by polyacrylamide gel electrophoresis in the absence of reducing agent and their composition determined after reductive cleavage and analysis in a second-dimensional gel. The most prominent cross-linked species produced by diamide treatment of of resting platelets are (A) cytoskeletal protein homopolymers, such as myosin heavy chain dimer and actin oligomers, and (B) high molecular weight material consisting of homo- or heteropolymers of cytoskeletal proteins and 230,000, 170,000, 100,000, 55,000, and 52,000 dalton proteins. DTSP treatment forms similar complexes and also cross-links membrane glycoproteins IIb and III into high molecular weight material. Thrombin activation of platelets before treatment with diamide or DTSP results in increased cross-linking of myosin and increased incorporation of several proteins, particularly myosin and glycoproteins IIb and III, into high molecular weight material. The results provide evidence for reorganization of cytoskeletal and membrane proteins during platelet function.

Amino acid composition and molecular weight of Botrytis cinerea laccase

1977 ◽  
Vol 16 (7) ◽  
pp. 1051-1052 ◽  
Author(s):  
Alfred M. Mayer ◽  
Irith Marbach ◽  
Assa Marbach ◽  
Ada Sharon
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Botrytis Cinerea ◽  
Acid Composition
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