The 3H-labelling of bilirubin.
Ontology highlight
ABSTRACT:
SUBMITTER: Hancock FE
PROVIDER: S-EPMC1163883 | biostudies-other | 1976 Aug
REPOSITORIES: biostudies-other
Similar Datasets
Project description:A one-step procedure has been developed for the preparation of [3H]bilirubin IX-alpha in good yield from unlabelled bilirubin. Irradiation of an aqueous solution of [3H]bilirubin IX-alpha in the presence of human serum albumin results in the covalent attachment of the bilirubin to the protein. Preliminary degradation studies have been carried out to locate the site of attachment of the bilirubin to the albumin.
| S-EPMC1161221 | biostudies-other
Project description:1. The pathway of haem breakdown in living rats was studied by using 18O in the oxygen that the animals consumed. By cannulation of the common bile duct and collection of bile, labelled bilirubin was isolated and its mass spectrum determined. One set of results was obtained for a rat to which haemoglobin had been intravenously administered and another set obtained for a rat that was not given exogenous haem. Isomerization of bilirubin IXalpha to the XIIIalpha and IIIalpha isomers did not occur to any significant extent. The 18O-labelling pattern obtained in the bilirubin was consistent with a Two-Molecule Mechanism, whereby the terminal lactam oxygen atoms of bilirubin are derived from different oxygen molecules. The consequences of this mechanism are discussed in terms of the possible intermediates of the catabolic pathway. 2. 18O-labelled bilirubin appeared in the bile in less than 10 min after exposure of the animals to labelled oxygen. This result suggests that all of the chemical transformations involving production of biliverdin, reduction to bilirubin and conjugation of the bilirubin are fast processes. 3. The quantitative recovery of label obtained in the experiments suggests that there is little or no exchange of newly synthesized bilirubin with existing bilirubin pools in the animal.
| S-EPMC1183896 | biostudies-other
Project description:Neutralized perchloric acid extracts of intra-abdominally proliferating Ehrlich mouse ascites-tumour cells harvested after 24 h exposure to [2-3H]inositol were analysed by Mono Q HR5/5 anion-exchange h.p.l.c. using an ammonium formate/phosphoric acid gradient or by ambient-pressure small-column anion-exchange chromatography (Bio-Rad AG 1-X8, 200-400 mesh). The results showed that cellular ATP contained aberrant 3H label in excess of 3H in the isomers of InsP3 and InsP4. The putative ATP 3H radioactivity showed: (i) h.p.l.c. run time as the material causing the largest A254 peak traced, (ii) precise spiking with ATP and [14C]ATP and (iii) specific absorption to charcoal. Moreover, enzymic conversion of ATP into ADP changed putative ATP 3H into putative ADP 3H. In addition, aberrant 3H labelling of cellular ADP and GTP was detected, although at a lower level.
| S-EPMC1138244 | biostudies-other
Project description:[3H]N-Phenylmaleimide has been used to covalently label in a specific manner the substrate-protected thiol groups of the enzyme protochlorophyllide reductase. In membrane preparations from oat (Avena sativa) and runner-bean (Phaseolus vulgaris) seedlings, two related peptides of mol.wts. 35000/37000 and 34000/35000 respectively and showing properties expected of the reductase have been identified, whereas the same technique with barley (Hordeum vulgare) extracts resulted in labelling a single peptide of mol.wt. 38000. Evidence is presented that both NADPH and protochlorophyllide are required for protection of the essential thiol groups on the reductase in oat extracts, a situation favouring a ternary complex as the structure for the photoactive enzyme--substrates intermediate.
| S-EPMC1162858 | biostudies-other
Project description:Using highly purified unconjugated [3H]bilirubin (UCB), we measured UCB binding to delipidated human serum albumin (HSA) and its uptake by basolateral rat liver plasma membrane vesicles, in both the absence and presence of an inside-positive membrane potential. Free UCB concentrations ([Bf]) were calculated from UCB-HSA affinity constants (K'f), determined by five cycles of ultrafiltration through a Centricon-10 device (Amicon) of the same solutions used in the uptake studies. At HSA concentrations from 12 to 380 microM, K'f (litre/mol) was inversely related to [HSA], irrespective of the [Bf]/[HSA] ratio. K'f was 2.066 x 10(6) + (3.258 x 10(8)/[HSA]). When 50 mM KC1 was isoosmotically substituted for sucrose, the K'f value was significantly lower {2.077 x 10(6) + (1.099 x 10(8)/[HSA])}. The transport occurred into an osmotic-sensitive space. Below saturation ([Bf] < or = 65 nM), both electroneutral and electrogenic components followed saturation kinetics with respect to [Bf], with K(m) values of 28 +/- 7 and 57 +/- 8 nM respectively (mean +/- S.D., n = 3, P < 0.001). The Vmax was greater for the electrogenic than for the electroneutral component (112 +/- 12 versus 45 +/- 4 pmol of UCB. mg-1 of protein. 15 s-1, P < 0.001). Sulphobromophthalein trans-stimulated both electrogenic (61%) and electroneutral (72%) UCB uptake. These data indicate that: (a) as [HSA] increases, K'f decreases, thus increasing the concentration of free UCB. This may account for much of the enhanced hepatocytic uptake of organic anions observed with increasing [HSA]. (b) UCB is taken up at the basolateral membrane of the hepatocyte by two systems with K(m) values within the range of physiological free UCB levels in plasma. The electrogenic component shows a lower affinity and a higher capacity than the electroneutral component. (c) It is important to calculate the actual [Bf] using a K'f value determined under the same experimental conditions (medium and [HSA]) used for the uptake studies.
| S-EPMC1217447 | biostudies-other
Project description:Mono[3H]propionyl-alpha-bungarotoxin, prepared with N-succinimidyl [2,3-3H]propionate (sp. radioactivity 50 Ci/mmol) and purified to homogeneity by electrofocusing, retains its biological activity and stability. Rate constants for its binding to acetylcholine receptor were 4.4-fold lower than for unlabelled toxin; no dissociation was detectable. Analysis of enzymic digests of toxin showed 3H is located mainly of entirely in epsilon-propionyl-lysine.
| S-EPMC1162686 | biostudies-other
Project description:1. 3-sn-Phosphatidylcholine was identified as the major lipid in cotyledons from the developing seeds of soya bean, linseed and safflower when tissue was steamed before lipid extraction. The proportion of oleate in this lipid decreased markedly and that of the polyunsaturated C(18) fatty acids increased when detached developing cotyledons were incubated for up to 3h. Similar but less pronounced changes occurred in diacylglycerol, which had a fatty acid composition resembling that of the 3-sn-phosphatidylcholine from cotyledons of the same species. 2. [1-(14)C]Acetate supplied to detached cotyledons was incorporated into the acyl moieties of mainly 3-sn-phosphatidylcholine, 1,2-diacylglycerol and triacylglycerol. Initially label was predominantly in oleate, but subsequently entered at accelerating rates the linoleoyl moieties of the above lipids in soya-bean and safflower cotyledons and the linoleoyl and linolenyl moieties of these lipids in linseed cotyledons. In pulse-chase experiments label was rapidly lost from the oleate of 3-sn-phosphatidylcholine and accumulated in the linoleoyl and linolenoyl moieties of this phospholipid and of the di- and tri-acylglycerols. 3. [2-(3)H]Glycerol was incorporated into the glycerol moieties of mainly 3-sn-phosphatidylcholine and di- and tri-acylglycerols of developing linseed and soya-bean cotyledons. The label entered the phospholipid and diacylglycerol at rates essentially linear with time from the moment the substrate was supplied, and entered the triacylglycerol at an accelerating rate. With linseed cotyledons the labelled glycerol was incorporated initially mainly into species of 3-sn-phosphatidylcholine and diacylglycerol that contained oleate, but accumulated with time in more highly unsaturated species. In pulse-chase experiments with linseed cotyledons, label was lost from both 3-sn-phosphatidylcholine and diacylglycerol, preferentially from the dioleoyl species, and accumulated in triacylglycerol, mainly in species containing two molecules of linolenate. 4. The results suggest a rapid turnover of 3-sn-phosphatidylcholine during triacylglycerol accumulation in developing oilseeds, and are consistent with the operation of a biosynthetic route whereby oleate initially esterified to the phospholipid is first desaturated, then polyunsaturated fatty acids transferred to triacylglycerol, via diacylglycerol. The possible role of oleoyl phosphatidylcholine as a substrate for oleate desaturation is discussed.
| S-EPMC1183910 | biostudies-other
Project description:The glucose oxidase-peroxidase (GOD-POD) method used to measure serum unbound bilirubin (UB) suffers from direct bilirubin (DB) interference. Using a bilirubin-inducible fluorescent protein from eel muscle (UnaG), a novel GOD-POD-UnaG method for measuring UB was developed. Newborn sera with an indirect bilirubin/albumin (iDB/A) molar ratio of <0.5 were classified into four groups of DB/total serum bilirubin (TB) ratios (<5%, 5-10%, 10-20%, and ≥20%), and the correlation between the UB levels and iDB/A ratio was examined. Linear regression analysis was performed to compare UB values from both methods with the iDB/A ratio from 38 sera samples with DB/TB ratio <5% and 11 samples with DB/TB ratio ≥5%. The correlation coefficient (r) between UB values and the iDB/A ratio for the GOD-POD method was 0.8096 (DB/TB ratio <5%, n = 239), 0.7265 (5-10%, n = 29), 0.7165 (10-20%, n = 17), and 0.4816 (≥20%, n = 16). UB values using the GOD-POD-UnaG method highly correlated with the iDB/A ratio in both <5% and ≥5% DB/TB ratio sera (r = 0.887 and 0.806, respectively), whereas a low correlation (r = 0.428) occurred for ≥5% DB/TB ratio sera using the GOD-POD method. Our GOD-POD-UnaG method can measure UB levels regardless of the presence of DB.
| S-EPMC7555467 | biostudies-literature
Project description:Atazanavir Bilirubin-related Side Effects
| PRJNA417884 | ENA
Project description:Atazanavir Bilirubin-related Side Effects
| PRJNA417885 | ENA