XXIInd congress of theoretical and applied chemistry. High molecular weight compound section

1970 ◽  
Vol 12 (5) ◽  
pp. 1351-1355
Author(s):  
S.L. Davydova
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Applied Chemistry ◽  
High Molecular Weight Compound ◽  
Compound Section

scholarly journals Cutinase-Like Enzyme from the Yeast Cryptococcus sp. Strain S-2 Hydrolyzes Polylactic Acid and Other Biodegradable Plastics

2005 ◽  
Vol 71 (11) ◽  
pp. 7548-7550 ◽  
Author(s):  
Kazuo Masaki ◽  
Numbi Ramudu Kamini ◽  
Hiroko Ikeda ◽  
Haruyuki Iefuji
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Polylactic Acid ◽  
Biodegradable Plastics ◽  
Remote Homology ◽  
High Molecular Weight Compound ◽  
Polybutylene Succinate

ABSTRACT A purified lipase from the yeast Cryptococcus sp. strain S-2 exhibited remote homology to proteins belonging to the cutinase family rather than to lipases. This enzyme could effectively degrade the high-molecular-weight compound polylactic acid, as well as other biodegradable plastics, including polybutylene succinate, poly (ε-caprolactone), and poly(3-hydroxybutyrate).

SOME FACTORS AFFECTING THE KÖNIGS–KNORR SYNTHESIS OF GLYCOSIDES

1961 ◽  
Vol 39 (10) ◽  
pp. 2025-2034 ◽  
Author(s):  
H. R. Goldschmid ◽  
A. S. Perlin
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Silver Oxide ◽  
Condensation Reaction ◽  
Side Reaction ◽  
Ortho Ester ◽  
Factors Affecting ◽  
High Molecular Weight Compound ◽  
Elemental Iodine

Glycosyl halides decompose readily in the presence of silver oxide under conditions generally used for the Königs–Knorr synthesis of glycosides. This "side reaction" probably accounts for the low yields commonly obtained in the synthesis of oligosaccharides, particularly those involving the formation of a glycosidic union through an unreactive secondary position. The rate of the side reaction, as well as that of the normal condensation reaction, is dependent on the condition of the silver oxide, and is retarded markedly by elemental iodine. This latter effect appears to be related to the improved yield obtained in Königs–Knorr syntheses when iodine is used. Among the products formed in the decomposition of 2,3,4,6-tetra-O-acetyl-α-D-mannopyranosyl bromide are 2,3,4,6-tetra-O-acetyl-D-mannose, a heptaacetyl 1,2,1′-linked dimeric orthoacetate, and a second high-molecular-weight compound that also shows ortho ester properties.

Synthesis and Properties of Substituted Germylhydrazines

1972 ◽  
Vol 50 (4) ◽  
pp. 553-561 ◽  
Author(s):  
L. K. Peterson ◽  
K. I. Thé
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Degree Of Substitution ◽  
Spectral Measurements ◽  
Mass Spectral ◽  
High Molecular Weight Compound ◽  
Condensed Product ◽  
New Compounds

By using reactions between Me3GeBr or Me2GeCl2 and appropriate lithium hydrazide salts, the following new compounds were prepared: Me2NN(R)GeMe3 (R = H, 1; Me, 2; GeMe3, 3; SiMe3, 4), Me3GeN(Me)NHGeMe3, 5a, MeNHN(GeMe3)2, 5b, (Me3Ge)2NN(Me)GeMe3, 6, Me3GeNHNHGeMe3, 7a, (Me3Ge)2NNH2, 7b, (Me)11Ge4N6H, 11, (Me2GeNNMe2)3, 12, Me2Ge[N(R′)NMe2]2 (R′ = Me, 13; SiMe3, 14). Thus the reaction of Me3GeBr with Li(MeN2H2) and with LiN2H3 gave mixtures of disubstituted isomers, 5a and b, and 7a and b, respectively, rather than mono-substituted derivatives. Reactions of Me2GeCl2 gave (i) an unresolvable, highly condensed product with LiN2H3; (ii) the high molecular weight compound 11, with Li(MeN2H2); and (iii) the cyclic trigermazane 12 with Me2NNHLi; the extent of self-condensation is a function of the degree of substitution of the hydrazine moiety. Reactions with protic reagents (H2O, MeOH, anhydrous HCl) effect cleavage of the Ge—N bond in germylhydrazines. New compounds were characterized on the basis of i.r., n.m.r., and mass spectral measurements.

Mechanochemical processes accompanying metal grinding in the presence of a high-molecular-weight compound

2012 ◽  
Vol 445 (2) ◽  
pp. 138-140 ◽  
Author(s):  
V. P. Reva ◽  
D. V. Onishchenko ◽  
V. V. Chakov ◽  
B. A. Voronov
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
High Molecular Weight Compound

Microtubule motors and other maps

1990 ◽  
Vol 48 (3) ◽  
pp. 1-1
Author(s):  
Richard B. Vallee
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Cytoplasmic Dynein ◽  
Organelle Transport ◽  
Structural Components ◽  
Microtubule Associated Proteins ◽  
Microtubule Motors ◽  
Associated Proteins ◽  
The Subject ◽  
Intracellular Motility

Microtubules are involved in a number of forms of intracellular motility, including mitosis and bidirectional organelle transport. Purified microtubules from brain and other sources contain tubulin and a diversity of microtubule associated proteins (MAPs). Some of the high molecular weight MAPs - MAP 1A, 1B, 2A, and 2B - are long, fibrous molecules that serve as structural components of the cytamatrix. Three MAPs have recently been identified that show microtubule activated ATPase activity and produce force in association with microtubules. These proteins - kinesin, cytoplasmic dynein, and dynamin - are referred to as cytoplasmic motors. The latter two will be the subject of this talk.Cytoplasmic dynein was first identified as one of the high molecular weight brain MAPs, MAP 1C. It was determined to be structurally equivalent to ciliary and flagellar dynein, and to produce force toward the minus ends of microtubules, opposite to kinesin.

Studies on the Functionality of Newly Synthesized Fibrinogen after Treatment of Acute Myocardial Infarction with Streptokinase, Increase in the Rate of Fibrinopeptide Release

1993 ◽  
Vol 70 (06) ◽  
pp. 0978-0983 ◽  
Author(s):  
Edelmiro Regano ◽  
Virtudes Vila ◽  
Justo Aznar ◽  
Victoria Lacueva ◽  
Vicenta Martinez ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Molecular Weight ◽  
Steady State ◽  
High Molecular Weight ◽  
Coronary Arteries ◽  
Risk Index ◽  
Weight Fraction ◽  
High Molecular Weight Fraction ◽  
Fibrinopeptide A

SummaryIn 15 patients with acute myocardial infarction who received 1,500,000 U of streptokinase, the gradual appearance of newly synthesized fibrinogen and the fibrinopeptide release during the first 35 h after SK treatment were evaluated. At 5 h the fibrinogen circulating in plasma was observed as the high molecular weight fraction (HMW-Fg). The concentration of HMW-Fg increased continuously, and at 20 h reached values higher than those obtained from normal plasma. HMW-Fg represented about 95% of the total fibrinogen during the first 35 h. The degree of phosphorylation of patient fibrinogen increased from 30% before treatment to 65% during the first 5 h, and then slowly declined to 50% at 35 h.The early rates of fibrinopeptide A (FPA) and phosphorylated fibrinopeptide A (FPAp) release are higher in patient fibrinogen than in isolated normal HMW-Fg and normal fibrinogen after thrombin addition. The early rate of fibrinopeptide B (FPB) release is the same for the three fibrinogen groups. However, the late rate of FPB release is higher in patient fibrinogen than in normal HMW-Fg and normal fibrinogen. Therefore, the newly synthesized fibrinogen clots faster than fibrinogen in the normal steady state.In two of the 15 patients who had occluded coronary arteries after SK treatment the HMW-Fg and FPAp levels increased as compared with the 13 patients who had patent coronary arteries.These results provide some support for the idea that an increased synthesis of fibrinogen in circulation may result in a procoagulant tendency. If this is so, the HMW-Fg and FPAp content may serve as a risk index for thrombosis.

The Effect of Dextran of Various Molecular Weight on the Coagulation in Dogs

1961 ◽  
Vol 06 (01) ◽  
pp. 015-024 ◽  
Author(s):  
Sven Erik Bergentz ◽  
Oddvar Eiken ◽  
Inga Marie Nilsson
Keyword(s):  
Molecular Weight ◽  
Body Weight ◽  
High Molecular Weight ◽  
Bleeding Time ◽  
Factor Vii ◽  
Low Molecular Weight ◽  
Factor V ◽  
Coagulation Mechanism ◽  
Coagulation Defects

Summary1. Infusions of low molecular weight dextran (Mw = 42 000) to dogs in doses of 1—1.5 g per kg body weight did not produce any significant changes in the coagulation mechanism.2. Infusions of high molecular weight dextran (Mw = 1 000 000) to dogs in doses of 1—1.5 g per kg body weight produced severe defects in the coagulation mechanism, namely prolongation of bleeding time and coagulation time, thrombocytopenia, pathological prothrombin consumption, decrease of fibrinogen, prothrombin and factor VII, factor V and AHG.3. Heparin treatment of the dogs was found to prevent the decrease of fibrinogen, prothrombin and factor VII, and factor V otherwise occurring after injection of high molecular weight dextran. Thrombocytopenia was not prevented.4. In in vitro experiments an interaction between fibrinogen and dextran of high and low molecular weight was found to take place in systems comprising pure fibrinogen. No such interaction occurred in the presence of plasma.5. It is concluded that the coagulation defects induced by infusions of high molecular weight dextran are due to intravascular coagulation.

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