Tryptic Enzymes from Certain Commercial Fishes

1941 ◽  
Vol 5b (3) ◽  
pp. 217-226 ◽  
Author(s):  
W. W. Johnston
Keyword(s):  
High Activity ◽  
Intestinal Mucosa ◽  
High Yield ◽  
Pyloric Caeca ◽  
Commercial Use ◽  
Digestive Organs ◽  
Hydrolysis Products

An examination of fish digestive organs showed that only the pyloric caeca and intestine showed a sufficiently high yield and a sufficiently high activity to make their commercial use feasible. The intestine had approximately one-quarter the activity of the caeca. Mackerel caeca showed the highest activity and yield of any organ in four species of fish examined. No activating effect parallel to that of mammalian enterokinase on trypsinogen was demonstrated. By comparing the hydrolysis products of casein by pyloric caeca, intestinal mucosa, and hog pancreas, evidence was adduced showing that the enzymic constituents of these preparations are similar.

Iridium-Catalyzed Silylation of C-H bonds in Unactivated Arenes: A Sterically-Encumbered Phenanthroline Ligand Accelerates Catalysis Enabling New Reactivity

2019 ◽  
Author(s):  
Caleb Karmel ◽  
Zhewei Chen ◽  
John Hartwig
Keyword(s):  
High Activity ◽  
Functional Group ◽  
Activity Analysis ◽  
High Reactivity ◽  
High Yield ◽  
Phen Ligand ◽  
Mechanistic Studies ◽  
Phenanthroline Ligand ◽  
First Time ◽  
New System

We report a new system for the silylation of aryl C-H bonds. The combination of [Ir(cod)(OMe)]<sub>2</sub> and 2,9-Me<sub>2</sub>-phenanthroline (2,9-Me<sub>2</sub>phen) catalyzes the silylation of arenes at lower temperatures and with faster rates than those reported previously, when the hydrogen byproduct is removed, and with high functional group tolerance and regioselectivity. Inhibition of reactions by the H<sub>2</sub> byproduct is shown to limit the silylation of aryl C-H bonds in the presence of the most active catalysts, thereby masking their high activity. Analysis of initial rates uncovered the high reactivity of the catalyst containing the sterically hindered 2,9-Me<sub>2</sub>phen ligand but accompanying rapid inhibition by hydrogen. With this catalyst, under a flow of nitrogen to remove hydrogen, electron-rich arenes, including those containing sensitive functional groups, undergo silylation in high yield for the first time, and arenes that underwent silylation with prior catalysts react over much shorter times with lower catalyst loadings. The synthetic value of this methodology is demonstrated by the preparation of key intermediates in the synthesis of medicinally important compounds in concise sequences comprising silylation and functionalization. Mechanistic studies demonstrate that the cleavage of the aryl C-H bond is reversible and that the higher rates observed with the 2,9-Me<sub>2</sub>phen ligand is due to a more thermodynamically favorable oxidative addition of aryl C-H bonds.

Digestion and Digestive Enzymes in the Herring (Clupea harengus L.)

1935 ◽  
Vol 1 (3) ◽  
pp. 145-157 ◽  
Author(s):  
Helen I. Battle
Keyword(s):  
Intestinal Mucosa ◽  
Digestive Enzymes ◽  
Clupea Harengus ◽  
Acidic Condition ◽  
Pyloric Caeca ◽  
Temperature Range ◽  
Gastric Contents

Crustacean food is partially broken down and digested in the caecum of the stomach of the herring. It becomes more finely divided in the pyloric sac and consists of an oily chyme, intermingled with chitin, mucus and bacterial clumps in the pyloric caeca and intestine. The acidic condition of the gastric contents is probably instrumental in the reddening of chitinous food in the tract. Pepsin from the stomach and trypsin from the pyloric caeca increase in digestive power over a temperature range from 2.4 to 37.5 °C. The stomach secretes a protease (pepsin), a weak amylase, and possibly a weak lipase. The pyloric caeca secrete a strong protease (trypsin), a strong amylase, and a lipase rendered active by bile. The intestinal mucosa exhibits lipolytic and amylolytic ferments, while the bile has some amylolytic properties.

Lipolytic enzymes of the digestive organs of the crown-of-thorns starfish (Acanthaster planci: Comparison of the stomach and pyloric caeca

1989 ◽  
Vol 92 (4) ◽  
pp. 637-643 ◽  
Author(s):  
M-Christiane Brahimi-Horn ◽  
Maria L. Guglielmino ◽  
Lindsay G. Sparrow ◽  
Raymond I. Logan ◽  
Peter J. Moran
Keyword(s):  
Acanthaster Planci ◽  
Lipolytic Enzymes ◽  
Pyloric Caeca ◽  
Digestive Organs

THE HANDLING OF SOYA ALPHA-GALACTOSIDES BY A NORMAL AND A GALACTOSEMIC CHILD

PEDIATRICS ◽  
1965 ◽  
Vol 36 (2) ◽  
pp. 231-235
Author(s):  
Richard Gitzelmann ◽  
Salvatore Auricchio
Keyword(s):  
Blood Glucose ◽  
Intestinal Mucosa ◽  
Healthy Child ◽  
Dietary Supplementation ◽  
Small Intestinal Mucosa ◽  
Red Cell ◽  
Galactosidase Activity ◽  
Hydrolysis Products ◽  
Small Intestinal ◽  
Alpha Galactosidase

1. No alpha-galactosidase activity in homogenates of human small intestinal mucosa was demonstrated either with stachyose, raffinose, or melibiose. 2. In a healthy child, oral raffinose and melibiose loads failed to produce changes in blood glucose, blood galactose, or red cell galactose-1-phosphate. Trace amounts of either saccharide were excreted in the urine. Following the raffinose load, diarrhea occurred and raffinose and melibiose as well as their hydrolysis products were found in the feces. 3. In a galactosemic patient, red cell galactose-1-phosphate rose as expected after ingestion of 2 gm of galactose. No such rise was seen after administration of equivalent and of double equivalent amounts of stachyose. Prolonged dietary supplementation with raffinose did not significantly alter non-fasting erythrocyte galactose-1-phosphate. 4. It is concluded that soybean formulas are generally safe for galactosemic infants; however, caution is advised for patients suffering from diarrhea.

Isolation and Characteristics of High-Activity Heparin

1979 ◽  
Author(s):  
Isidore Danishefsky ◽  
Steven Radoff ◽  
Michael Bender ◽  
German Villanueva
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Affinity Chromatography ◽  
High Activity ◽  
Intestinal Mucosa ◽  
Chromogenic Substrate ◽  
Highly Active ◽  
The Common ◽  
Heparin Preparation ◽  
Inhibition Of Thrombin

Chromatography of heparin from beef lung on Biogel P-100 yielded a series of fractions with different anticoagulant activities. The assays for activity of the products were based on their effect in accelerating the inhibition of thrombin by antithrombin. Residual thrombin was measured by its effect on the clotting of fibrinogen and by its action on the chromogenic substrate H-D-Phe-Pip-Arg-p-nitroanilide (S-2238). Fractions with as much as 6-10 times the clotting activity of the original heparin, were obtained. The activities per mg of heparin were highest in fractions eluted in, or near, the void volume of the column. In addition to glucosamine and uronlc acid, the most active fractions contained considerable amounts of protein. The amino acids included glycine, serine, threonine, alanine, aspartate and glutamate. Experiments with heparin from porcine intestinal mucosa gave similar results.Affinity chromatography of the highly active fractions on antithrombin-Sepharose showed that all of these materials are bound to the gel and that relatively large proportions are eluted with 1 M and 3 M NaCl.It is concluded that the common heterodisperse heparin preparation contain a series or components ranging from extremely high activities to no activity. On the basis of the elution volumes of the fractions, the activities are directly related to molecular weight.

The use of multimodal resins for purification of therapeutic monoclonal antibodies

2021 ◽  
pp. 10-16
Author(s):  
Aleksey Vladimirovich Tsivov ◽  
Viktor Andreevich Kuvshinov ◽  
Denis Alekseevich Mazalyov ◽  
Mariya Nikolaevna Zavorueva ◽  
Vera Vyacheslavovna Eliseeva ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
High Activity ◽  
High Purity ◽  
High Yield ◽  
Orphan Diseases ◽  
Cancer Genetic ◽  
Biological Studies ◽  
Therapeutic Monoclonal Antibodies

Obtaining protein samples with high yield, high purity, and high activity is the foundation for most modern biological studies. Besides, highly purified protein preparations, such as monoclonal antibodies, have been widely used in the treatment of cancer, genetic and orphan diseases.

Reaktionen des donorfreien (CF3)2Cd mit Phosphor(V)halogeniden: Difluorcarben-Einschiebungen und Direktsynthese von (CF3)3PF2 / Reactions of Donor-Free (CF3)2Cd with Phosphorus(V) Halides: Insertion of Difluorocarbene and Direct Synthesis of (CF3)3PF2

1998 ◽  
Vol 53 (12) ◽  
pp. 1455-1460 ◽  
Author(s):  
Reint Eujen ◽  
Ralf Haiges
Keyword(s):  
Nmr Spectra ◽  
Direct Synthesis ◽  
High Yield ◽  
Cadmium Fluoride ◽  
Hydrolysis Products ◽  
Isomerization Mechanism ◽  
Related Compounds

Abstract Difluorocarbene which is quantitatively eliminated from donor-free bis(trifluoromethyl)- cadmium below 0 °C inserts smoothly into the P-F bonds of PF5 to form (CF3)3 PF2 in high yield. Due to the fast conversion of P-Cl bonds into P-F bonds by cadmium fluoride, PCl5 forms (CF3)3PF2 as well, and a direct synthesis of (CF3)3PF2 with ca. 70 % yield starting from CdEt2, CF3I and PCl5 is reported. Whereas no insertion of CF2 into the axial bonds of (CF3)3PF2 has been detected, reaction of (CF3)2Cd with (CF3)3 PCl2 gives the new tetrakis( haloalkyl)fluorophosphoranes (CF)3 (CF2C1)PF, (CF3)3 (CFCl2 )PF, (CF3)2 (CF2Cl)2PF and (CF3)3 (CCl3)PF. The NMR spectra of these and related compounds and of their hydrolysis products (CF3)3(CF3-nCln)PO are reported. The formation of the higher chlorinated phosphoranes is discussed in terms of an isomerization mechanism presumably involving carbene elimination-reinsertion processes.

Iridium-Catalyzed Silylation of C-H bonds in Unactivated Arenes: A Sterically-Encumbered Phenanthroline Ligand Accelerates Catalysis Enabling New Reactivity

2019 ◽  
Author(s):  
Caleb Karmel ◽  
Zhewei Chen ◽  
John Hartwig
Keyword(s):  
High Activity ◽  
Functional Group ◽  
Activity Analysis ◽  
High Reactivity ◽  
High Yield ◽  
Phen Ligand ◽  
Mechanistic Studies ◽  
Phenanthroline Ligand ◽  
First Time ◽  
New System

We report a new system for the silylation of aryl C-H bonds. The combination of [Ir(cod)(OMe)]<sub>2</sub> and 2,9-Me<sub>2</sub>-phenanthroline (2,9-Me<sub>2</sub>phen) catalyzes the silylation of arenes at lower temperatures and with faster rates than those reported previously, when the hydrogen byproduct is removed, and with high functional group tolerance and regioselectivity. Inhibition of reactions by the H<sub>2</sub> byproduct is shown to limit the silylation of aryl C-H bonds in the presence of the most active catalysts, thereby masking their high activity. Analysis of initial rates uncovered the high reactivity of the catalyst containing the sterically hindered 2,9-Me<sub>2</sub>phen ligand but accompanying rapid inhibition by hydrogen. With this catalyst, under a flow of nitrogen to remove hydrogen, electron-rich arenes, including those containing sensitive functional groups, undergo silylation in high yield for the first time, and arenes that underwent silylation with prior catalysts react over much shorter times with lower catalyst loadings. The synthetic value of this methodology is demonstrated by the preparation of key intermediates in the synthesis of medicinally important compounds in concise sequences comprising silylation and functionalization. Mechanistic studies demonstrate that the cleavage of the aryl C-H bond is reversible and that the higher rates observed with the 2,9-Me<sub>2</sub>phen ligand is due to a more thermodynamically favorable oxidative addition of aryl C-H bonds.

scholarly journals A Green Synthesis and Antibacterial Activity of N-Arylsulfonylhydrazone Compounds

2019 ◽  
Vol 25 (1) ◽  
pp. 152-156 ◽  
Author(s):  
Qian Yang ◽  
Wangwang Hao ◽  
Yangqing He ◽  
Qian Zhang ◽  
Xiaojiao Yu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Green Synthesis ◽  
High Activity ◽  
Antibacterial Activities ◽  
High Yield ◽  
Green Method ◽  
Aryl Aldehydes

AbstractA green method has been developed for the synthesis of N-arylsulfonylhydrazones via a simple grindstone procedure. By grinding mixtures of benzensulfonyl hydrazides and a series of aryl aldehydes or ketones in the mortar using L-tyrosine as catalyst, 24 N-arylsulfonylhydrazones were synthesized in a few minutes with high yield. All compounds were screened for their antibacterial activities. Most of them exhibit some antibacterial activities especially for 3d, 3l and 3v showing high activity against Staphylococcus aureus and Escherichia coli.

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