Enzyme-modified microelectrodes were developed for the indirect amperometric detection of acetylcholine and choline following separation by capillary electrophoresis. Electrodes were prepared by first sequentially electrodepositing polypyrrole and polytyramine from the monomers on a 200-microm platinum electrode. The polymer bilayer provides enhanced selectivity and pendant amino groups for cov...

The choline oxidase was first described by Bernheim and Bernheim (1). Later it was shown (2) that choline at pH 6.7 was oxidized to betaine aldehyde which was then only slowly oxidized further, whereas at pH 7.8 the oxidation proceeded rapidly to betaine. This indicated that betaine aldehyde was oxidized by another enzyme system, and Klein and Handler (3) were able to show that its oxidation re...

The membrane of vesicular stomatitis virus could be readily enriched with exogenous cholesterol by exposing virion suspensions to serum lipoproteins forming complexes with cholesterol or to a carrier of polyvinylpyrrolidone/bovine serum albumin mixed with cholesterol. These procedures increased the cholesterol content of the virion membrane f rom -35 to -60% of the total lipid. Endogenous chole...

methvlation can occur. It was found that after feeding choline-methyl-C14 to plants, radioactive betaine and dimethylglycine had been produced. Choline could give rise to betaine either by transferring its methyl groups to glycine, or some methylated glycine, to yield betaine, or oxidation of choline to betaine could occur. The experiments of Cromwell and Rennie (5) and of Bregoff and Delwiche ...

We developed a convenient chromogenic assay method for the activity of sphingomyelinase (SMase) from Bacillus cereus. SMase reaction was quenched by Zn(2+), and the released phosphocholine was converted into a choline by the action of alkaline phosphatase. After that, the choline was converted into a chromogenic dye by the actions of choline oxidase and peroxidase in the presence of EDTA to tra...

Hepatic metabolism of long-chain fatty acids was studied in male rats fed a defined choline-deficient (CD) diet with and without choline and after methotrexate (MTX) administration. Peroxisomal beta-oxidation was increased approximately 4-fold in the peroxisome-enriched fraction of CD-fed animals, whereas the catalase activity was increased 1.3-fold. The urate oxidase activity was marginally af...

The results of liver perfusion experiments of Guggenheim and Loeffler (2) suggested that choline is oxidized to betainealdehyde (formylmethyltrimethyl ammonium ion). The products of reactions in vitro (3-6) exhibited the properties of betainealdehyde and betaine. It was shown that these products are formed by two enzymes of rat liver (7), choline oxidase of mitochondria (8, 9), and betainealdeh...

The aim of the study is to open a new scope for organic electrochemical transistors based on PEDOT:PSS, a material blend known for its stability and reliability. These devices can leverage molecular electrocatalysis by incorporating small amounts of nano-catalyst during the transistor manufacturing (spin coating). This methodology is very simple to implement using the know-how of nanochemistry ...

The synthesis ofglycinebetaine may proceed by two possible routes: (a) by the stepwise methylation of glycine, with sarcosine and dimethylglycine as intermediates, or (b) by the stepwise methylation of ethanolamine to choline with subsequent oxidation of the latter base. In certain animal tissues there is abundant evidence of the formation of betaine by oxidation of choline, and this step would...