scholarly journals Proteine als Schutzstoffe gegenüber dem Gefriertod der Zelle

1970 ◽  
Vol 25 (8) ◽  
pp. 834-842 ◽  
Author(s):  
U. Heber ◽  
M. Kempfle
Keyword(s):  
Molecular Weight ◽  
Frost Tolerance ◽  
Thylakoid Membranes ◽  
Weight Basis ◽  
Unit Weight ◽  
Low Molecular Weight ◽  
Complete Protection ◽  
Highly Active ◽  
Heat Stable ◽  
Better Than

Two protein factors from hardy leaves were highly active in preventing the inactivation of photophosphorylation of washed thylakoid membranes which takes place during freezing of thylakoids in the absence of protective compounds. Non-hardy leaves did not yield protective protein material. On a unit weight basis, protection by the protein factors was 10 to 100 times better than protection by compounds of low molecular weight such as sucrose, glycerol or dimethylsulfoxide. Very low amounts of the protein factors, which alone were scarcely protective, considerably reduced the concentration of sucrose required for the complete protection of thylakoids during freezing. The protein factors were heat-stable and had a molecular weight between 10 000 and 20 000 daltons. It is assumed that they contribute to and are in part responsible for the frost tolerance of hardy plant material.

Neutralisation of Heparan Sulphate and Low Molecular Weight Heparin by Protamine

1985 ◽  
Vol 53 (01) ◽  
pp. 086-089 ◽  
Author(s):  
A R Hubbard ◽  
C A Jennings
Keyword(s):  
Molecular Weight ◽  
Plasma Proteins ◽  
Low Molecular Weight Heparin ◽  
Heparan Sulphate ◽  
Activated Partial Thromboplastin Time ◽  
Weight Basis ◽  
Low Molecular Weight ◽  
Protamine Sulphate ◽  
At Iii ◽  
Reference Preparation

SummaryThe neutralisation by protamine sulphate (PS) of heparan sulphate (HS), a low molecular weight heparin (LMWH), and a reference preparation of unfractionated heparin (UH), was studied by activated partial thromboplastin time (APTT) and anti-Xa clotting assays. UH was most easily neutralised in the APTT assay by PS (on a weight for weight basis), followed by LMWH and HS. The neutralisation of APTT activity by PS closely followed the loss of activity in the anti-Xa clotting assay, when plasma was used as the source of At III. When the anti-Xa clotting assay was carried out using purified At III in place of plasma, HS and LMWH were neutralised by much lower amounts of PS and resembled UH neutralisation more closely. Resistance of HS anti-Xa activity to PS neutralisation decreased with increasing plasma dilution. The presence of bovine albumin with purified At III concentrate increased the resistance of HS to PS neutralisation. It is concluded that PS binding to UH, HS and LMWH is probably related more to their degree of sulphation than molecular weight and that non-specific interactions between PS and plasma proteins inhibit the binding of PS to HS and LMWH.

STUDIES ON THE ISOLATION AND NATURE OF THE 'TERREGENS FACTOR'

1954 ◽  
Vol 32 (1) ◽  
pp. 400-406 ◽  
Author(s):  
M. O. Burton ◽  
F. J. Sowden ◽  
A. G. Lochhead
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Ferric Iron ◽  
Test Organism ◽  
The Other ◽  
Inorganic Salts ◽  
Low Molecular Weight ◽  
Straight Chain ◽  
Heat Stable ◽  
Growth Promoting

A procedure is described for the production and concentration of the 'terregens factor' (TF), a bacterial growth promoting substance synthesized by Arthrobacter pascens and essential for the growth of Arthrobacter terregens. From culture filtrates of A. pascens cultivated in a medium of inorganic salts and sucrose, concentrates of TF may be obtained that are active at 0.001 μgm. Per ml., heat stable and contain about 12.7% nitrogen. Acid hydrolysis yielded a number of amino acids, including glutamic acid, glycine, α–alanine, valine, leucine, proline, lysine, and arginine, as well as some unidentified compounds; however, TF does not appear to be a low molecular weight straight chain peptide.Although TF contains no iron, it combines readily with ferrous or ferric iron to form reddish-brown complexes with this metal. Activity for A. terregens is shown by certain iron containing complexes as hemin, coprogen, and ferrichrome. On the other hand none is shown by cytochrome or pulcherrimin; however, aspergillic acid, structurally related to the latter, possesses some growth promoting activity for the test organism.

Effect of Various Curing Agents On the Chemical Stability of Epoxy Resins

CORROSION ◽  
1961 ◽  
Vol 17 (1) ◽  
pp. 11t-20t ◽  
Author(s):  
RONALD L. DeHOFF
Keyword(s):  
Molecular Weight ◽  
Chemical Stability ◽  
Epoxy Resins ◽  
Room Temperature ◽  
Low Molecular Weight ◽  
Curing Agent ◽  
Corrosion Prevention ◽  
Curing Agents ◽  
Outdoor Weathering ◽  
Better Than

Abstract The epoxy resins most widely used in corrosion prevention are liquids of low molecular weight which can be converted to hard, tough, chemically resistant polymers by the use of various curing agents. Unlike other thermosetting resins such as polyesters, the curing agents may produce chemical linkages in the final polymers that differ from those present in the uncured form. Hence, the properties of cured epoxy resins are likely dependent upon, and may even reflect the properties of the curing agent used. Some seven different epoxy resin systems were exposed to various chemical environments and evaluatd for changes in dimensional stability and flexural strengths over a six month period. From the data presented herein, only limited conclusions may be drawn. Heat cured systems fare better than room temperature cured systems in every case. Anhydride cured epoxy resins show greater resistance to outdoor weathering than amine cured systems. 5.4.5, 6.6.8

Changes of the Polypeptide Composition in Thylakoid Membranes during Differentiation

1990 ◽  
Vol 45 (3-4) ◽  
pp. 253-257 ◽  
Author(s):  
Magdolna Droppa ◽  
Jiri Masojidek ◽  
Gábor Horváth
Keyword(s):  
Molecular Weight ◽  
Chloroplast Development ◽  
Early Stage ◽  
Relative Concentration ◽  
Thylakoid Membranes ◽  
Low Molecular Weight ◽  
Polypeptide Composition ◽  
Lhc Ii

Changes in membrane polypeptide composition during greening of etiolated maize were investigated to confirm the existence of the developmental polypeptides of 12 - 15 kDa described recently in virescent soybean mutant [M. Droppa, M. L. Ghirardi, G. Horváth, and A. Melis, Biochim. Biophys. Acta 932, 138 - 145 (1988)]. These low molecular weight polypeptides were the most abundant proteins at the early stage of greening, but were largely absent from fully developed thylakoids. During greening the relative concentration of the 12-15 kDa polypeptides were inversely proportional to that of LHC II, suggesting a role of these polypeptides in the assembly of the LHC II and/or chloroplast development.

Photosynthesis and metabolism of marine algae. VIII. Incorporation of 14C into the polysaccharides metabolized by Fucus vesiculosus during pulse labeling experiments

1972 ◽  
Vol 50 (1) ◽  
pp. 191-197 ◽  
Author(s):  
R. G. S. Bidwell ◽  
Elizabeth Percival ◽  
Berit Smestad
Keyword(s):  
Molecular Weight ◽  
Sequential Extraction ◽  
Marine Algae ◽  
Alginic Acid ◽  
Fucus Vesiculosus ◽  
Fresh Medium ◽  
Low Molecular Weight ◽  
Acid Extract ◽  
Highly Active ◽  
Residual Material

Samples of Fucus vesiculosus fronds were allowed to assimilate 14CO2 for 10 min and 3 h. In a second experiment fronds were allowed to grow for 10 min in 14CO2 and were then transferred to fresh medium containing 12CO2. Samples were taken immediately, after 30 min, and after 2 h. Sequential extraction and fractionation of the polysaccharides from each of the five samples gave 14C-labeled laminaran, xylogalactofucoglucuronan (A), xyloglucuronogalactofucan (B) (these polysaccharides are named in the order of the increasing proportions of their constituent sugars), fucoidan (C), alginic acid, and residual polysaccharide material containing mainly glucose with some galactose. The activities of each of the polysaccharides, the residual material, and their constituent sugars were measured. Highly active low molecular weight carbohydrates, present in the acid extract, are the suggested precursors of the polysaccharides. The fucose-containing polysaccharides represent the extremes of a family of polymers; it is postulated from these studies that (A) is transformed into fucoidan via polysaccharide (B) in this alga.

A heat stable low molecular weight inhibitor of lysosomal cysteine proteinases in human serum

1983 ◽  
Vol 110 (2) ◽  
pp. 449-455 ◽  
Author(s):  
Francis Gauthier ◽  
Maurice Pagano ◽  
Frédéric Esnard ◽  
Henri Mouray ◽  
Robert Engler
Keyword(s):  
Molecular Weight ◽  
Human Serum ◽  
Low Molecular Weight ◽  
Cysteine Proteinases ◽  
Heat Stable

scholarly journals A comparison between the properties of low and medium molecular weight phenol formaldehyde resin-treated laminated compreg oil palm wood

2017 ◽  
Vol 19 (3) ◽  
pp. 1-11 ◽  
Author(s):  
G. Aizat ◽  
A. Zaidon ◽  
S. H. Lee ◽  
S. B. Edi ◽  
B. Paiman
Keyword(s):  
Molecular Weight ◽  
Oil Palm ◽  
Phenolic Resin ◽  
Phenol Formaldehyde ◽  
Phenol Formaldehyde Resin ◽  
Formaldehyde Resin ◽  
Low Molecular Weight ◽  
Hot Press ◽  
Plastic Bag ◽  
Better Than

In order to improve the inherently poor properties of oil palm wood (OPW), this study examines the effects of resin molecular weight, diffusion time and compression ratio on the properties of laminated compreg OPW. Treating solutions used were medium molecular weight phenol formaldehyde (MmwPF) and low molecular weight phenol formaldehyde (LmwPF). OPW strips were soaked in the treating solutions for 24 h before wrapping in a plastic bag and leaving them for diffusion for 2, 4 and 6 days, respectively. Then, three-layer laminated compreg OPW were fabricated and compressed in hot press at 150°C for 20 minutes to achieve compression ratios of 55%, 70% and 80%. Results indicated that dimensional stability and mechanical properties of the phenolic resin treated laminated compreg OPW were significantly better than the untreated laminates. MmwPF-treated laminates exhibited inferior properties in comparison to that of LmwPF-treated laminates. Nevertheless, MmwPF-treated laminated compreg OPW emitted significantly lesser formaldehyde.

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