Isolation and identification of alpha-methyloctanylcarnitines from human urine

Medium-chain acylcarnitines were isolated from human urine using a combination of chloroform-methanol extraction, silicic acid column and molecular sieving chromatography and preparative HPLC. Three purified acylcarnitines were analyzed by fast atom bombardment mass spectrometry and were also saponified and the free fatty acids analyzed by gas chromatography and mass spectrometry. Combined electron impact mass spectrometry and fast atom bombardment mass spectrometry and periodate oxidation for location of double bonds, demonstrated the occurrence of delta 6-octenylcarnitine, 2-methyloctanylcarnitine and 2-methyl-delta 6-octenylcarnitine. These acylcarnitines were present in the thirteen urines obtained from normal humans, but were not detected in urines from three individuals who had been on total parenteral nutrition for more than a year. The occurrence of alpha-methyl medium-chain acylcarnitines in human urine indicates a role for carnitine in excretion (detoxification) of these acyl derivatives.     

Isolation and identification of S-adenosylmethionine from human urine

Procedures are described for the isolation and identification of adenosylmethionine from human urine. Previously described preliminary separative procedures using anion and cation exchange columns and an XAD-4 resin column have been extended to permit the separation of adenosylmethionine. The adenosylmethionine has been identified by conversion to methylthioadenosine followed by rechromatography of the latter compound with three different types of columns and elution systems. Mean adenosylmethionine values for urine were as follows: adults, 0.26; children, 0.36 nmole/mumole creatinine. Recovery of adenosylmethionine added to urine and determined by this separative procedure was 52%.     

ISolation and identification of a sulfur-containing metabolite of spironolactone from human urine

In the urine of normal subjects Who were given an oral dose of 500 mg spironolactone (3-(3-oxo-7α-acetylthio-17β-hydroxy-4-androsten-17α-yl)-propionic acid γ-lactone; Aldactone^R) together with 100, uCi H-20, 21 spironolactone, a so far unknown major metabolite has been detected by thin layer chromatography. The metabolite then could be isolated by means of counter-current-distribution. According to masspectral and magnetic resonance data, the metabolite has been assigned the structure of 3-(3-oxo-7α-niethyl sulfonyl-6β, 17β-dihydroxy-4-androsten-17α-yl)-propionic acid γ-lactone. By oxidation of the corresponding methylsulfinyl compound — another already known metabolite of spironolactone-with m-chloroperbenzoic acid, a compound has been isolated which proved to be identical with the new metabolite according to TIC, MS and NMR.     

Isolation and identification of L-beta-aspartyl-Llysine and L-gamma-glutamyl-L-ornithine from normal human urine.

L-beta-Aspartyl-L-lysine and L-gamma-glutamyl-L-ornithine were isolated from pooled normal human urine and each peptide was shown to be identical with the authentic peptides. The concentrations of these dipeptides in the urine of individual subjects were determined directly by using a new buffer sequence on a standard ion exchange chromatographic amino acid analyzer with a sensitivity of 10(-10) mol. In urine from normal subjects ranging in age from 12 to 64 years, mean values of 1.47 mumol/g of creatinine of L-gamma-glutamyl-L-ornithine and 8,24 mumol/g of creatinine of L-beta-aspartyl-L-lysine were found. The urine of children under 10 years of age contained, relative to creatinine excretion, more L-beta-aspartyl-L-lysine and L-gamma-glutamyl-L-ornithine than that of older children and adults. All urines contained substantially larger concentrations of L-beta-aspartyl-L-lysine than of L-gamma-glutamyl-L-ornithine. Both peptides were found in urine collected after 21 hr of fasting in lower concentrations than found in urine from nonfasting subjects. The urinary concentrations of both peptides did not appear to be influenced by race or sex.     

A time-resolved fluoroimmunoassay for 18-oxocortisol and 18-hydroxycortisol. Development of a monoclonal antibody to 18-oxocortisol

Patients with primary aldosteronism and with glucocorticoid-suppressible aldosteronism excrete in the urine excessive amounts of the hybrid steroids 18-hydroxycortisol and 18-oxocortisol. The measurement of these steroids aids in the differential diagnosis of various adrenal disorders. We have produced mouse monoclonal antibodies against 18-oxocortisol and polyclonal antibodies against 18-hydroxycortisol and describe a time-resolved fluoroimmunoassay (TR-FIA) technique for the measurement of these steroids in the urine. We have also compared this assay with an ELISA technique for these compounds. We also describe the preparation of in-house Eu(III)-labeled avidin and an enhancement solution and compared to a commercially available Eu(III)-labeled streptavidin and enhancement solutions. The monoclonal antibodies against 18-oxocortisol are sensitive and have a high level of specificity. The TR-FIA technique using in-house prepared reagents or commercial ones were indistinguishable from each other, but at a significant saving. The TR-FIA technique was more sensitive and had a greater precision than the ELISA technique for both steroids.     

Isolation and identification of hydroxyproline analogues of bradykinin in human urine

Hydroxyproline (Hyp) analogues of bradykinin and lysyl-bradykinin, in which the third residue of bradykinin, proline, is replaced by hydroxyproline, were isolated from human urine. Their amino acid sequences were confirmed by both amino acid and sequence analyses, and also by comparison of their chromatographic behavior with that of synthetic peptides. The possibility that Lys-Ala3-bradykinin, isolated by Mindroiu et al. [(1986) J. Biol. Chem. 261, 7407-7411] from human urine, was actually Lys-Hyp3-bradykinin is discussed.     

Characterization of a new flavin metabolite from human urine

A new flavin metabolite comprising approximately 5% of the total flavin of human urine was isolated and characterized using absorption and fluorescence spectra, oxidation-reduction and hydrolysis data, and ninhydrin reactions. The flavin is a derivative associated with a peptide residue in ester linkage from an amino acid carboxyl to the ribityl chain of riboflavin, probably at the 5'-terminus.     

Isolation and identification of 16alpha, 18-dihydroxydeoxycorticosterone from human adrenal gland incubations

Incubations of 1,2-³H-18-hydroxydeoxycorticosterone with human adrenal glands resulted in conversion to a more highly hydroxylated material in addition to other material. By derivative formation, gas chromatography — mass spectrometry, and nuclear magnetic resonance spectroscopy, the structure of this material was shown to be 16_α, 18-dihydroxydeoxycorticosterone. Possible biological activity of this compound is discussed.     

Isolation and identification of urinary beta-aspartyl dipeptides and their concentrations in human urine.

beta-Aspartyl-methionine, -aspartic acid and -glutamic acid and gamma-glutamyl-threonine and -glycine were isolated and identified in human urine by ion-exchange chromatography, high-voltage paper electrophoresis, acid hydrolysis and determination of N-terminal amino acids of the isolated compounds, and comparison of their behaviors in paper electrophoresis and chromatography with those of the authentic compounds. The concentrations of acidic beta-aspartyl dipeptides in human urine were determined using an amino acid analyzer. Their concentrations were as follows: beta-aspartyl-glycine, male, 44.4 +/- 8.5, female, 61.4 +/- 18.9, child, 83.7 +/- 27.1; -alanine, male, 11.0 +/- 4.9, female, 20.7 +/- 12.0, child, 25.3 +/- 9.1; -glutamic acid, male, 10.0 +/- 3.7, female, 23.0 +/- 8.5, child, 20.4 +/- 7.5; -serine, male, 9.9 +/- 2.8, female, 13.6 +/- 3.8, child, 14.9 +/- 4.7; -aspartic acid, male, 4.3 +/- 1.0, female, 9.1 +/- 2.2, child, 18.4 +/- 6.5; -threonine, male 3.9 +/- 0.9, female, 5.8 +/- 1.1, child, 13.2 +/- 4.9 mumol/g creatinine (mean +/- S.D.). The order of the sum of their concentrations tended to be child greater than female greater than male. Patients receiving intravenous hyperalimentation also excreted acidic beta-aspartyl dipeptides into urine in amounts similar to those in females and in a pattern similar to that observed in healthy persons. This finding indicates that urinary beta-aspartyl dipeptides were probably of endogenous origin because oral nutrition was stringently excluded in these patients.