The structures of new protein farnesyltransferase inhibitors, andrastins A-C, were elucidated. The cyclopentane ring of andrastins exhibited keto-enol tautomerism, which made the structure hard to elucidate. Therefore, the structure of andrastin A was elucidated by INADEQUATE and 13C-13C couplings using 13C-labeled andrastin A. The absolute configuration of the p-bromobenzoyl derivative of andr...

The non-extractable residues of the fungicide cyprodinil formed in heterotrophic cell suspension cultures of wheat were studied by application of [2-pyrimidyl-14C] or [2-pyrimidyl-13C]cyprodinil. The main objective was to examine whether solid-state and liquid 13C NMR spectroscopy can be used to examine plant bound residues of pesticides. For 14C experiments, wheat suspensions grown on glucose ...

Carrying the apoE ε4 allele (E4+ ) is the most important genetic risk for Alzheimer’s disease. Unlike non-carriers (E4- ), E4+ seem not to be protected against Alzheimer's disease when consuming fish. We hypothesised that this may be linked to a disturbance in n-3 DHA metabolism in E4+. The aim of the present study was to evaluate [13C]DHA metabolism over 28 d in E4+ v. E4-. A total of forty pa...

The dihydrolipoyl transacetylase component of the pyruvate dehydrogenase complex catalyzes a reversible reaction between acetyl-CoA and dihydrolipoamide that results in the formation of S-acetyldihydrolipoamide. We have used 13C nuclear magnetic resonance to investigate this reaction using exogenous forms of dihydrolipoamide in place of the protein-bound substrate. With substrate levels of dihy...

In vivo spin spin relaxation time (T2) heterogeneity of hyperpolarized [13C,15N2]urea in the rat kidney was investigated. Selective quenching of the vascular hyperpolarized 13C signal with a macromolecular relaxation agent revealed that a long-T2 component of the [13C,15N2]urea signal originated from the renal extravascular space, thus allowing the vascular and renal filtrate contrast agent poo...

Effects of peripheral venous injection of glucagon and insulin on [l-13C]glucose incorporation into hepatic glycogen of rats were studied by 13C NMR in vivo. Each animal was given a continuous somatostatin infusion and a 100-mg intravenqus injection of [1-13C] glucose in NMR experiments or unlabeled glucose in parallel experiments for determination of serum glucose. Insulin administration cause...

Guinea pig heart metabolism was studied in vivo by 13C NMR at 20.18 MHz. High-quality proton-decoupled 13C NMR spectra with excellent signal-to-noise ratios and resolution could be obtained in 6 min. Natural-abundance spectra showed resonances that could be assigned to fatty acids, but glycogen was not seen. During intravenous infusion of D-[1-13C]glucose and insulin, the time course of myocard...

Biosynthetically directed fractional 13C labeling of the proteinogenic amino acids is achieved by feeding a mixture of uniformly 13C-labeled and unlabeled carbon source compounds into a bioreaction network. Analysis of the resulting labeling pattern enables both a comprehensive characterization of the network topology and the determination of metabolic flux ratios. Attractive features with rega...

We evaluated the applicability of stable isotopic tracers to the study of intramuscular fatty acid metabolism by infusing both [U-13C]palmitate and [1-13C]oleate intravenously for 4 h into fasted conscious rats. Skeletal muscles were sequentially biopsied, and the concentration and 13C enrichment of fatty acids were measured by gas chromatography/combustion/isotope ratio mass spectrometry. Thro...