The relationship between molecular weight and antifreeze polypeptide activity in marine fish

1986 ◽  
Vol 64 (3) ◽  
pp. 578-582 ◽  
Author(s):  
Ming H. Kao ◽  
Garth L. Fletcher ◽  
Nam C. Wang ◽  
Choy L. Hew
Keyword(s):  
Molecular Weight ◽  
Thermal Hysteresis ◽  
Freezing Temperature ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Molecular Weights ◽  
Shorthorn Sculpin ◽  
Myoxocephalus Scorpius ◽  
Antifreeze Peptides ◽  
Antifreeze Activity

Previous studies have established that the capacity of the glycopeptide antifreezes to depress the freezing temperature of aqueous solutions is positively correlated with molecular weight. The present study was carried out to determine whether a similar correlation existed within the antifreeze peptides. Two approaches were used. Initially, the antifreeze activity (thermal hysteresis) curves of antifreeze peptides from winter flounder, Pseudopleuronectes americanus (molecular weight, 3300), shorthorn sculpin, Myoxocephalus scorpius (molecular weight, 4000), ocean pout, Macrozoarces americanus (molecular weight, 6000), and sea raven, Hemitripterus americanus (molecular weight, 9700), were compared. In the second approach, a more specific comparison was made of two different sized antifreeze peptide components (molecular weights, 2900 and 4000) from the shorthorn sculpin. In both approaches, antifreeze peptide activity was positively correlated with molecular weight and the curve illustrating this relationship suggests that any reduction in molecular weight below 3300 will result in a disproportionate decline in activity. The relatively small antifreeze peptides from the winter flounder and shorthorn sculpin had greater activity than did glycopeptide antifreezes of similar size. However, glycopeptide antifreezes with a molecular weight of 10 000 or more had activities that exceeded that of any known antifreeze peptide. Increases in molecular weight of antifreeze peptides above 4000 resulted in a decline in antifreeze activity per milligram protein. Therefore, in terms of ability to depress the freezing temperature, there appears to be no advantage in evolving large antifreeze peptide molecules.

Antifreeze proteins from the shorthorn sculpin, Myoxocephalus scorpius: isolation and characterization

1980 ◽  
Vol 58 (5) ◽  
pp. 377-383 ◽  
Author(s):  
Choy L. Hew ◽  
Garth L. Fletcher ◽  
V. S. Ananthanarayanan
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Secondary Structure ◽  
Antifreeze Proteins ◽  
Winter Flounder ◽  
Isolation And Characterization ◽  
Shorthorn Sculpin ◽  
Approximate Molecular Weight ◽  
Myoxocephalus Scorpius ◽  
Antifreeze Activity

The antifreeze proteins (AFP) of the shorthorn sculpin, Myoxocephalus scorpius, were isolated and compared with the AFP of the winter flounder. The shorthorn sculpin was found to contain one major and one minor antifreeze protein with an approximate molecular weight of 10 000 – 11 000 in the winter. The major AFP was isolated and characterized. It had many characteristics in common with the flounder AFP studied in our laboratories. These characteristics included its seasonal appearance, size, amino acid composition, the abundance of alanine in the composition, the extent of antifreeze activity, and the nature of the secondary structure. It is suggested that both the sculpin and flounder AFP are structurally homologous and belong to the same type of polypeptide antifreeze.

Heterogeneity of antifreeze polypeptides from the Newfoundland winter flounder, Pseudopleuronectes americanus

1984 ◽  
Vol 62 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Ron M. Fourney ◽  
Shashikant B. Joshi ◽  
Ming H. Kao ◽  
Choy L. Hew
Keyword(s):  
Molecular Weight ◽  
High Performance Liquid Chromatography ◽  
Gel Electrophoresis ◽  
High Performance ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Reverse Phase ◽  
Antifreeze Polypeptides

The heterogeneity of Newfoundland winter flounder antifreeze polypeptides was analyzed by reverse phase high performance liquid chromatography and by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Seven antifreeze polypeptide components could be readily demonstrated. Five of the components were similar in molecular weight (3300) and amino acid composition. Two of the antifreeze polypeptide components were larger (4500) and contained valine. The two major components (components 6 and 8) were identical to those reported earlier from our laboratories.

How does the brain control the pituitary's release of antifreeze synthesis inhibitor?

1984 ◽  
Vol 62 (5) ◽  
pp. 839-844 ◽  
Author(s):  
G. L. Fletcher ◽  
M. J. King ◽  
C. L. Hew
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Antifreeze Proteins ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Synthesis Inhibitor ◽  
Pituitary Glands ◽  
The Central Nervous System ◽  
The Brain ◽  
Antifreeze Activity

Previous studies of winter flounder (Pseudopleuronectes americanus) demonstrated that the pituitary inhibits the synthesis of antifreeze proteins during the summer and that the inhibition is removed with the approach of winter. Assuming that the pituitary is under the control of the central nervous system, the question posed was, Does the central nervous system stimulate the release of the pituitary antifreeze inhibitory factor during the summer or inhibit its release during the winter? Two experiments were carried out. In the first, flounder were hypophysectomized and a number of them were given pituitary autotransplants prior to the spring loss of plasma antifreeze. During July, flounder containing functional autotransplants had lost the capacity to synthesize antifreeze proteins and their plasma antifreeze activity had disappeared. In the second experiment, hypophysectomy and pituitary transplantation was carried out in the fall prior to the winter onset of antifreeze biosynthesis. Flounder containing functional auto- or homo-transplants showed no evidence of plasma antifreeze activity, whereas intact controls and hypophysectomized flounder had levels typical of winter fish. These results indicate that the central nervous system normally inhibits the pituitary glands release of antifreeze inhibitor during the winter.

Hepatic metallothionein in the winter flounder (Pseudopleuronectes americanus)

1985 ◽  
Vol 63 (7) ◽  
pp. 1602-1609 ◽  
Author(s):  
M. A. Shears ◽  
G. L. Fletcher
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Metal Binding ◽  
Winter Flounder ◽  
Low Molecular Weight ◽  
Pseudopleuronectes Americanus ◽  
Metal Binding Protein ◽  
Hepatic Metallothionein

A low molecular weight, metal-binding protein, characterized as metallothionein, was isolated from the liver cytosols of winter flounder injected with zinc or cadmium. This identity was confirmed by its amino acid composition, which was similar to that of metallothioneins isolated from the intestinal mucosal cytosol of zinc-injected flounder and from liver cytosols of other species of fish and mammals.

The relationship between metallothionein and intestinal zinc absorption in the winter flounder

1984 ◽  
Vol 62 (11) ◽  
pp. 2211-2220 ◽  
Author(s):  
M. A. Shears ◽  
G. L. Fletcher
Keyword(s):  
Molecular Weight ◽  
Zinc Uptake ◽  
Winter Flounder ◽  
Zinc Binding ◽  
Low Molecular Weight ◽  
Zinc Absorption ◽  
Marine Teleost ◽  
Pseudopleuronectes Americanus ◽  
Chromatographic Techniques ◽  
The Relationship

Chromatographic techniques were used to investigate the presence of zinc-binding proteins in the intestinal mucosal cytosols of a marine teleost, the winter flounder (Pseudopleuronectes americanus). A low molecular weight, zinc-binding protein, characterized as metallothionein, was isolated from the intestinal cytosols of zinc-injected flounder. Metallothionein synthesis was induced in the intestine of the flounder by parenteral injections of zinc. However, studies conducted to assess the involvement of metallothionein in gastrointestinal zinc uptake indicated that its presence in the intestinal cytosol was not associated with any enhancement or depression of zinc uptake. These findings contrast with current hypotheses concerning metallothionein function in mammalian intestines.

Investigation by HPLC of the Catabolism of Recombinant Tissue Plasminogen Activator in the Rat

1988 ◽  
Vol 60 (01) ◽  
pp. 107-112 ◽  
Author(s):  
Roy Harris ◽  
Louis Garcia Frade ◽  
Lesley J Creighton ◽  
Paul S Gascoine ◽  
Maher M Alexandroni ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Half Life ◽  
Recombinant Tissue Plasminogen Activator ◽  
Rat Plasma ◽  
High Molecular Weight Complex ◽  
Molecular Weights ◽  
Major Activity ◽  
Tissue Plasminogen

SummaryThe catabolism of recombinant tissue plasminogen activator (rt-PA) was investigated after injection of radiolabelled material into rats. Both Iodogen and Chloramine T iodination procedures yielded similar biological activity loss in the resultant labelled rt-PA and had half lives in the rat circulation of 1 and 3 min respectively. Complex formation of rt-PA was investigated by HPLC gel exclusion (TSK G3000 SW) fractionation of rat plasma samples taken 1-2 min after 125I-rt-PA injection. A series of radiolabelled complexes of varying molecular weights were found. However, 60% of the counts were associated with a single large molecular weight complex (350–500 kDa) which was undetectable by immunologically based assays (ELISA and BIA) and showed only low activity with a functional promoter-type t-PA assay. Two major activity peaks in the HPLC fractions were associated with Tree t-PA and a complex having a molecular weight of ̴ 180 kDa. HPLC fractionation to produce these three peaks at various timed intervals after injection of 125I-rt-PA showed each to have a similar initial rate half life in the rat circulation of 4-5 min. The function of these complexes as yet is unclear but since a high proportion of rt-PA is associated with a high molecular weight complex with a short half life in the rat, we suggest that the formation of this complex may be a mechanism by which t-PA activity is initially regulated and finally cleared from the rat circulation.

Permeability Enhancing and Chemotactic Activities of Lower Molecular Weight Degradation Products of Human Fibrinogen

1981 ◽  
Vol 45 (01) ◽  
pp. 090-094 ◽  
Author(s):  
Katsuo Sueishi ◽  
Shigeru Nanno ◽  
Kenzo Tanaka
Keyword(s):  
Molecular Weight ◽  
Degradation Products ◽  
Electron Microscopic Observation ◽  
Chemotactic Activity ◽  
Lower Molecular Weight ◽  
Electron Microscopic ◽  
Human Fibrinogen ◽  
Rabbit Skin ◽  
Molecular Weights ◽  
Active Fragments

SummaryFibrinogen degradation products were investigated for leukocyte chemotactic activity and for enhancement of vascular permeability. Both activities increased progressively with plasmin digestion of fibrinogen. Active fragments were partially purified from 24 hr-plasmin digests. Molecular weights of the permeability increasing and chemotactic activity fractions were 25,000-15,000 and 25,000 respectively. Both fractions had much higher activities than the fragment X, Y, D or E. Electron microscopic observation of the small blood vessels in rabbit skin correlated increased permeability with the formation of characteristic gaps between adjoining endothelial cells and their contraction.These findings suggest that lower molecular weight degradation products of fibrinogen may be influential in contributing to granulocytic infiltration and enhanced permeability in lesions characterized by deposits of fibrin and/or fibrinogen.

Toxicity of Heparinoids, with Special Reference to the Precipitation of Fibrinogen

1964 ◽  
Vol 12 (01) ◽  
pp. 232-261 ◽  
Author(s):  
S Sasaki ◽  
T Takemoto ◽  
S Oka
Keyword(s):  
Molecular Weight ◽  
Dextran Sulfate ◽  
Anticoagulant Activity ◽  
Molecular Structures ◽  
Severe Reaction ◽  
Clinical Use ◽  
Molecular Weights ◽  
Close Relationship

SummaryTo demonstrate whether the intravascular precipitation of fibrinogen is responsible for the toxicity of heparinoid, the relation between the toxicity of heparinoid in vivo and the precipitation of fibrinogen in vitro was investigated, using dextran sulfate of various molecular weights and various heparinoids.1. There are close relationships between the molecular weight of dextran sulfate, its toxicity, and the quantity of fibrinogen precipitated.2. The close relationship between the toxicity and the precipitation of fibrinogen found for dextran sulfate holds good for other heparinoids regardless of their molecular structures.3. Histological findings suggest strongly that the pathological changes produced with dextran sulfate are caused primarily by the intravascular precipitates with occlusion of the capillaries.From these facts, it is concluded that the precipitates of fibrinogen with heparinoid may be the cause or at least the major cause of the toxicity of heparinoid.4. The most suitable molecular weight of dextran sulfate for clinical use was found to be 5,300 ~ 6,700, from the maximum value of the product (LD50 · Anticoagulant activity). This product (LD50 · Anticoagulant activity) can be employed generally to assess the comparative merits of various heparinoids.5. Clinical use of the dextran sulfate prepared on this basis gave satisfactory results. No severe reaction was observed. However, two delayed reactions, alopecia and thrombocytopenia, were observed. These two reactions seem to come from the cause other than intravascular precipitation.

Molecular Weights of Factor VIII (AHF) and Factor IX (PTC) by Electron Irradiation

1962 ◽  
Vol 08 (02) ◽  
pp. 270-275 ◽  
Author(s):  
David L Aronson ◽  
John W Preiss ◽  
Michael W Mosesson
Keyword(s):  
Molecular Weight ◽  
Factor Viii ◽  
Electron Irradiation ◽  
Factor Ix ◽  
Molecular Weights

SummaryThe molecular weights of AHF (factor VIII) and of PTC (factor IX) have been estimated by their sensitivity to inactivation by 7 kilovolt electrons. The molecular weight of AHF was found to be 180 000 by this method and that of PTC was found to be 110 000.

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