Complete hydrolysis of dietary cholesterol esters during intestinal absorption

The proposed method determines the activity of cholesterol esterase (CEH) and takes advantage of its ability to catalyze the hydrolysis of cholesterol esters naturally present in human serum. The assay is based on Allain's method of spectrophotometric determination of cholesterol by means of cholesterol oxidase, peroxidase, but using 3,5-dichloro-dihydroxybenzenesulfonic acid (DHBS) as phenolic chromogen and human serum as a source of substrate for the CEH as a novelty. Furthermore, it is characterized by low costs and high precision. It can be employed to control the activity of CE preparations used for the preparation of enzymatic kits for the determination of cholesterol or for screening of potential bacterial enzyme producers.

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Darstellung von o-Phenylen-bis(dibromphosphan) — Reaktionsprodukte von o-Phenylen-bis(dichlorphosphan) / Synthesis of o-Phenylene-bis(dibromophosphane) — Reaction Products of o-Phenylene-bis(dichlorophosphane)

Zeitschrift für Naturforschung B ◽

10.1515/znb-1984-1215 ◽

1984 ◽

Vol 39 (12) ◽

pp. 1706-1710 ◽

Cited By ~ 5

Author(s):

H.-J. Wörz ◽

E. Quien ◽

H. P. Latscha

Keyword(s):

Hydrogen Peroxide ◽

Hydrogen Bromide ◽

Equimolar Amount ◽

Reaction Products ◽

Large Excess ◽

Cyclic Anhydride ◽

Complete Hydrolysis ◽

Hydrolysis Of

o-Phenylene-bis(dibromophosphane) (1) is prepared by reaction of P ,P,P′,P′-tetrakis(dim ethylamino)-o-phenylenediphosphane with hydrogen bromide in ether. The reaction of o-phenylene- bis(dichlorophosphane) (2) with CH3OH in ether yields o-phenylene-bis(phosphonousacid- dimethylester) (3). The Michaelis-Arbuzov conversion of 3, either by heat or by catalytic amounts of CH3I in toluene, yields ophenylene-bis(methylphosphinic-acid-methylester) (4). The reduction of 2 must be carried out with a large excess of LiAlH4 (1:4) in ether to give o-phenylenediphosphane (5). The cyclic anhydride (6) of P.P′-dichloro-o-phenylenediphosphonous acid is formed when 2 is hydrolyzed in ether with an equimolar amount of water. Complete hydrolysis of 2 with an excess of water gives o-phenylenediphosphonous acid (7). With hydrogen peroxide o-phenylenediphosphonic acid (8) can be isolated.

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A Simple Method for the Quantification of Free Isocyanates on the Surface of Cellulose Nanocrystals upon Carbamation using Toluene Diisocyanate

Surfaces ◽

10.3390/surfaces2020032 ◽

2019 ◽

Vol 2 (2) ◽

pp. 444-454 ◽

Cited By ~ 7

Author(s):

Hatem Abushammala

Keyword(s):

Elemental Analysis ◽

Cellulose Nanocrystals ◽

Toluene Diisocyanate ◽

Hydroxyl Group ◽

Simple Method ◽

Complete Hydrolysis ◽

Amine Groups ◽

Ph Increase ◽

Hydrolysis Of ◽

Cellulose Surface

In many reports, cellulose and nanocellulose have been carbamated using 2,4-toluene diisocyanate (2,4-TDI) to allow the grafting of molecules or polymers onto their surfaces. Such a process usually involves the reaction of the more reactive isocyanate group of TDI (para-NCO) selectively with a hydroxyl group from the cellulose surface, followed by the reaction of the free isocyanate (ortho-NCO) with a desired molecule. After the first step, it is not possible, using elemental analysis, to determine the amount of ortho-NCO on the cellulosic surface, as an ideal para/ortho selectivity is difficult to obtain. This paper presents a simple method for the quantification of ortho-NCOs on the surface of cellulose nanocrystals upon TDI-based carbamation. It relies on the pH increase upon a complete hydrolysis of ortho-NCOs to amine groups using acidified dimethylsulfoxide. The method was found to be accurate and valid for a degree of substitution of up to 20%.

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THE FATE OF DNA-CONTAINING PARTICLES PHAGOCYTIZED BY MAMMALIAN CELLS

The Journal of Cell Biology ◽

10.1083/jcb.21.1.105 ◽

1964 ◽

Vol 21 (1) ◽

pp. 105-114 ◽

Cited By ~ 20

Author(s):

Klaus Bensch ◽

Gerald Gordon ◽

Leonard Miller

Keyword(s):

Acid Phosphatase ◽

Suspension Culture ◽

Mammalian Cells ◽

Complete Hydrolysis ◽

Hydrolysis Of

Particulate DNA protein coacervates were digested immediately after being phagocytized by L strain fibroblasts in suspension culture. Enlargement of the phagocytotic vacuoles occurred simultaneously with a loss of the electron opacity of the phagocytized particles. Cytochemical reactions positive for non-specific esterase, acid phosphatase, and nucleoside phosphatase in the phagocytotic vacuoles provided additional evidence for the probability of complete hydrolysis of the phagocytized nucleoprotein.

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Intestinal Absorption of Dipeptides Containing Glycine, Phenylalanine, Proline, β-Alanine or Histidine in the Rat

Clinical Science ◽

10.1042/cs0450849 ◽

1973 ◽

Vol 45 (6) ◽

pp. 849-858 ◽

Cited By ~ 6

Author(s):

D. J. Boullin ◽

R. F. Crampton ◽

Christine E. Heading ◽

D. Pelling

Keyword(s):

Intestinal Absorption ◽

Ion Exchange Chromatography ◽

Exchange Chromatography ◽

Peptide Absorption ◽

Physiological Conditions ◽

Anaesthetized Rats ◽

Tissue Homogenates ◽

Rate Of Hydrolysis ◽

Hydrolysis Of

1. The intestinal absorption of carnosine, glycylglycine, glycyl-d-phenylalanine, glycyl-l-phenylalanine, glycyl-l-proline and l-prolylglycine were investigated after intraluminal injection of dipeptide into anaesthetized rats. 2. With all six dipeptides, the intact substance was detected by ion-exchange chromatography in blood samples taken from the superior mesenteric vein. 3. The rate of hydrolysis of the dipeptides in tissue homogenates was measured in vitro. 4. The relative rates of hydrolysis varied by a factor of 300; there was an apparent inverse relationship between rate of hydrolysis and detection of intact peptide. 5. Peptide absorption was accompanied by increases in venous concentrations of the component amino acids, which appeared in proportions appropriate to the view that peptide absorption preceded hydrolysis. 6. It is suggested that slowly hydrolysed dipeptides may pass intact through the intestine wall under physiological conditions.

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The complete hydrolysis of peptides by a mixture of sepharose-bound peptidases

Biochemical Journal ◽

10.1042/bj1250080pb ◽

1971 ◽

Vol 125 (3) ◽

pp. 80P-81P ◽

Cited By ~ 6

Author(s):

H P J Bennett ◽

D F Elliott ◽

P J Lowry ◽

C McMartin

Keyword(s):

Complete Hydrolysis ◽

Hydrolysis Of

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1-(4-Nitrophenyl)-1H-1,2,3-Triazole-4-carbaldehyde: Scalable Synthesis and Its Use in the Preparation of 1-Alkyl-4-Formyl-1,2,3-triazoles

Organics ◽

10.3390/org2040024 ◽

2021 ◽

Vol 2 (4) ◽

pp. 404-414

Author(s):

Tomas Opsomer ◽

Kaat Valkeneers ◽

Ana Ratković ◽

Wim Dehaen

Keyword(s):

One Pot ◽

Complete Hydrolysis ◽

One Step ◽

Synthetic Intermediates ◽

Cornforth Rearrangement ◽

Scalable Synthesis ◽

The One ◽

Novel Applications ◽

Hydrolysis Of

1,2,3-Triazole-4-carbaldehydes are useful synthetic intermediates which may play an important role in the discovery of novel applications of the 1,2,3-triazole moiety. In this work, a one-step multigram scale synthesis of 4-formyl-1-(4-nitrophenyl)-1H-1,2,3-triazole (FNPT) as a preferred reagent for the synthesis of 1-alkyl-4-formyltriazoles is described, making use of the commercially available 3-dimethylaminoacrolein and 4-nitrophenyl azide. Next, the earlier reported reaction of FNPT with alkylamines is further explored, and for hexylamine, the one-pot sequential cycloaddition and Cornforth rearrangement is demonstrated. In addition, a useful protocol for the in situ diazotization of 4-nitroaniline is provided. This facilitated the complete hydrolysis of rearranged 4-iminomethyl-1,2,3-triazoles and allowed for the recycling of 4-nitrophenyl azide.

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