Rabbits were fed cholesterol-free, semipurified diets containing 42% (wt/wt) casein or 21% casein plus one of the following nitrogen sources: soy isolate, amino acid mixture simulating casein, amino acid mixture simulating soy isolate, formaldehyde-treated casein or formaldehyde-treated soy isolate. Two additional groups of rabbits were fed the 42% casein diet and the diet containing casein plus soy isolate to which 0.4% (wt/wt) pure formaldehyde was added, this amount being identical to the amount of formaldehyde present in the diets with formaldehyde-treated proteins. Growth was somewhat reduced on the three diets containing 42% casein. The diet containing 42% casein to which no formaldehyde had been added induced severe hypercholesterolemia, the level of serum cholesterol after 8 weeks being about 10 mmol/L. The hypercholesterolemia was markedly reduced by the replacement of half of the casein by soy isolate, formaldehyde-treated soy isolate or formaldehyde-treated casein. No significant reduction of the concentration of serum cholesterol was seen when half of the 42% casein was replaced by an amino acid mixture imitating either casein or soy isolate. Formaldehyde per se did not significantly influence the level of serum cholesterol. We conclude that the differential tertiary structure of intact casein and soy isolate is an important factor in determining the cholesterolemic responses in rabbits to these proteins.
Replacement of soy protein by casein in the cholesterol-free, semipurified diet of rabbits caused hypercholesterolemia within 7 days. After 36 days, the serum of casein-fed rabbits displayed elevated levels of free and esterified cholesterol and phospholipids, but not of triglycerides. Most of the excess of serum cholesterol in the casein group was localized in the LDL fraction, but there were marked variations in the density profile of the serum lipoproteins between individual rabbits. Dietary casein induced an increased content in liver of free and esterified cholesterol, but not of phospholipids and triglycerides. The molar ratio of free to esterified cholesterol in the liver was decreased by casein. In contrast, feeding casein resulted in an increase of this ratio in the serum.
Novel L-tartaric acid based stereodynamic biphenylbisphosphinite ligands with anilino linkers were prepared as cyclic diamide compounds. The influence of the constitutional substitution pattern of the amino group at the aniline moiety on the diastereoselective formation of the ligand was investigated. While the meta-anilino bridged ligands showed a highly dynamic behavior and no discrimination between (R ax ) and (S ax ) configuration, L-tartaric acid substitution on ortho-anilino bridged ligands leads to diastereoselective self-alignment of the central biphenol axis, which controls the stereoselectivity of the ligand and catalyst. The experimental findings were corroborated by theoretical calculations. In the rhodium-catalyzed enantioselective hydrogenation of methyl 2acetamidoacrylate (MAA), an enantiomeric ratio of 75 : 25 (R/S) was obtained for the ortho-substituted ligand.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.