alpha-Chymotrypsin exhibits photoswitchable activities in an organic solvent after covalent modification of the protein backbone with thiophenefulgide active ester (2). The thiophenefulgide-modified alpha-chymotrypsin exhibits reversible photoisomerizable properties between states (3)-E and (3)-C. The modified alpha-chymotrypsin, where nine lysine residues are substituted by thiophenefulgide un...

Cholesterol esterase of pancreatic juice origin and acyl coenzyme A:cholesterol acyltransferase, both associated with the intestinal mucosa, are implicated in the extensive esterification of exogenous cholesterol during absorption. To assess the role of each enzyme, [4-14C]cholesterol absorption into mesenteric lymph of rats with normal mucosal levels of both esterification enzymes was compared...

The coordinated control of cholesterol biosynthesis and esterification by 25-hydroxycholesterol was studied in the macrophage-like cell line P388D1. Since 25-hydroxycholesterol rapidly stimulated incorporation of [3H]oleate into the cholesteryl ester fraction of these cells, we have tested the possibility that the well-known inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA...

Methyl formate presents a challenge for the conventional chemical mechanisms assumed to guide interstellar organic chemistry. Previous studies of potential formation pathways for methyl formate in interstellar clouds ruled out gas-phase chemistry as a major production route, and more recent chemical kinetics models indicate that it may form efficiently from radical-radical chemistry on ice surf...

Relative to saturated fatty acids, trans-fatty acids/hydrogenated fat-enriched diets have been reported to increase low density lipoprotein (LDL) cholesterol levels and either decrease or have no effect on high density lipoprotein (HDL) cholesterol levels. To better understand the effect of trans-fatty acids/hydrogenated fat on HDL cholesterol levels and metabolism, 36 subjects (female, n = 18;...

Polyhydroxylated hybrid molecules have been synthesized using a protocol based on the regioselective acylation of the target compounds with activated dicarboxylic acids catalyzed by Novozym-435. The procedure implies that the mixed ester derivatives prepared and isolated from the first esterification step act as acylating agents in the second esterification step.

We examined, in muscle of lean and obese Zucker rats, basal, insulin-induced, and contraction-induced fatty acid transporter translocation and fatty acid uptake, esterification, and oxidation. In lean rats, insulin and contraction induced the translocation of the fatty acid transporter FAT/CD36 (43 and 41%, respectively) and plasma membrane-associated fatty acid binding protein (FABPpm; 19 and ...

Cholesterol oxides are atherogenic and can affect the activity of diverse important enzymes for the lipidic metabolism. The effect of 7b-hydroxycholesterol, 7-ketocholesterol, 25-hydroxycholesterol, cholestan-3b,5a,6b-triol,5,6b-epoxycholesterol, 5,6a-epoxycholesterol and 7a-hydroxycholesterol on esterification of cholesterol by lecithin:cholesterol acyl transferase (LCAT, EC 2.3.1.43) and the ...

In order to produce biodiesel from waste cooking oil and optimize its yield, a two-stage process of esterification/ transesterification has been used in this study. First, we used the acidic catalysts H2SO4 in order to diminish the content of free fatty acid (FFA) in oil that caused reducing the oil acidity from 6.1% to 0.57% through esterification. Then, the biodiesel was produced by transeste...

Esterification of chitosan with adipic acid catalyzed by immobilized Candida antarctica lipase B was carried out in this study. Response surface methodology (RSM) based on a four-factor- five-level small central composite design (SCCD) was employed to model and analyze the reaction. A total of 21 experiments representing different combinations of the four reaction parameters including ch...