Microbial fermentative preparation of l-[15N2]lysine and its tracer: Application to serum amino acid kinetic studies

Irving, Charles S.; Cooney, Charles L.; Brown, Laura T.; Gold, Daniel; Gordon, Jennifer; Klein, Peter

doi:10.1016/0003-2697(83)90139-2

Cited by 4 publications

(2 citation statements)

References 8 publications

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“…A heparin lock for blood sampling was placed in the opposite arm from the injection site. Blood samples (2 ml) were drawn immediately before and at 1, 2, 3,5,7,10,15,20,30,45,60,90,120,150,180,240, 300, and 360 min after isotope injection. An additional 3 ml of blood was collected immediately before and at 30, 60, 90, 120, 240, and 360 min after isotope injection.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Lysine and protein metabolism in young women. Subdivision based on the novel use of multiple stable isotopic labels.

Irving¹,

Thomas²,

Malphus³

et al. 1986

J. Clin. Invest.

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A multitracer stable isotope study of lysine kinetics was carried out in fasted adult female volunteers to determine whether a multicompartmental model that partitions protein synthesis and breakdown into at least two types of tissue components can be constructed from plasma and breath data. Five female subjects, maintained on formula diets, received L-113CIlysine (27 Mmol/ kg) as an i.v. bolus and L-1I5N2Ilysine (27 Atmol/kg) as an oral bolus 4 h postprandially. Plasma and breath samples were collected for 6 h. On an alternate day, subjects received NaH'3C03 (10 Atmol/kg) as an i.v. bolus and breath samples were collected for 6 h. Plasma tracer lysine levels were determined by gas chromatography-mass spectrometry isotope ratiometry, and breath 13C02 levels were measured by mass spectrometric gas isotope ratiometry. The tracer data could be fitted to a mammillary multicompartmental model that consisted of a lysine central compartment and slow-and fast-exchanging peripheral compartments containing 37, 38, and 324 gmol/kg, respectively. The rates of lysine oxidation, incorporation into protein, and release by protein breakdown were 21, 35, and 56 mmol/kg/h, respectively, in the fast-exchanging compartment, whereas the rates of protein synthesis and breakdown in the slow compartment were both 53 mmol/kg/min. These values corresponded to a whole-body lysine flux of 106 mmol/kg/h. The kinetic parameters were in excellent agreement with reported values obtained by constant-infusion methods. The measurements indicated that it will be possible to detect changes in amino acid pool sizes and protein synthesis and breakdown associated with the mobilization of protein stores from plasma and breath measurements in multitracer stable isotope experiments.

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Section: Methodsmentioning

confidence: 99%

“…Plasma levels ofendogenous lysine, ['5N2]1ysine, and [m3C1]lysine were determined by gas chromatography-mass spectrometry isotope ratiometry as described by Irving et al (10). Lysine was isolated from plasma (500 Ml) on a cation-exchange resin from which it was eluted with 1 ml of 3N NH4CI followed by 1 ml of water.…”

Section: Methodsmentioning

confidence: 99%