ABSTRACT
An attempt was made to establish the binding of N-(2,4-diphosphobenzyl)-1-amino-5-naphthalenesulfonic acid, DIPANS, as an estimator of conformation in the carbonmonoxy (CO)-hemoglobins (Hbs) of several vertebrates. DIPANS failed to bind menhaden I, trout I or tuna Hbs which are ligand insensitive. Below a pH of 7.0, DIPANS bound menhaden II, Bufo, Xenopus, and human Hbs with a binding stoichiometry greater than one. The charge of the DIPANS molecule does not control its binding to these Hbs. The binding to human CO-Hb can not be due to Hb conformation. For Xenopus Hbs and menhaden II, conformation predominates DIPANS binding. The binding to CO-Hb of DIPANS, can not be unambiguously attributed to the Hb's quaternary conformation.
Subject(s)
Hemoglobins/metabolism , Naphthalenesulfonates/blood , Animals , Bufonidae , Carboxyhemoglobin/metabolism , Humans , Hydrogen-Ion Concentration , Kinetics , Protein Binding , Protein Conformation , Species Specificity , Trout , Tuna , XenopusABSTRACT
A colorimetric method for determination of acetaminophen in serum, based on its reaction with 2-nitroso-1-naphthol-4-sulfonic acid, is described. The method is sensitive, rapid, and free from the interferences of serum matrix and most common drugs. The method can be performed manually or can be semiautomated. The results from this method correlate well with values determined by high-performance liquid chromatography.
Subject(s)
Acetaminophen/blood , Colorimetry/methods , Acetylcysteine/blood , Autoanalysis/methods , Humans , Indicators and Reagents , Kinetics , Naphthalenesulfonates/blood , Sodium NitriteABSTRACT
The absorption, distribution and excretion of the red azo dye carmoisine (Ext. D & C No. 10) was studied in male rats. [14C]Carmoisine was administered in a dose of 200 mg/kg (25 microCi) by gavage or in the same dose (200 mg/kg; 3 microCi) by intravenous injection, and radioactivity was measured in blood, tissue, faeces and urine at different times after dosing. After oral administration of the dye, no radioactivity was detected in the brain, adipose tissue, muscle, testes, spleen or lung, and recovery of the administered activity in faeces and urine was almost complete by 32 hr. The radioactivity profile of the blood indicated rapid but poor absorption of [14C]carmoisine, a maximum radioactivity content corresponding to 0.01% of the dose per ml of blood being reached within 10 min. The decay curve for 14C radioactivity in the blood after iv injection of [14C]carmoisine indicated rapid distribution to the tissues and could be described in terms of a two-compartment mathematical model. The highest levels of radioactivity occurred in the gastro-intestinal tract and liver after the injection but after 24 hr no radioactivity was detectable in these or other tissues. All the radioactivity was recovered in the faeces and urine in the 24 hr following iv injection, the 79% of the dose present in faeces indicating active excretion of the dye and its metabolites in the bile and poor reabsorption from the intestine. The bioavailability of [14C]carmoisine, calculated from the blood-radioactivity curves after oral and iv administration, was less than 10%.
Subject(s)
Coloring Agents/metabolism , Naphthalenesulfonates/metabolism , Administration, Oral , Animals , Carbon Radioisotopes , Coloring Agents/blood , Feces/analysis , Injections, Intravenous , Isotope Labeling , Male , Naphthalenesulfonates/blood , Rats , Rats, Inbred Strains , Tissue DistributionABSTRACT
The characteristics of the binding site in the first binding class of naphthol yellow-S (NY-S) on bovine serum albumin (BSA) were studied. The binding of NY-S to BSA at an equimolar ratio of each material resulted in a marked quenching of intrinsic fluorescence of BSA and a decrease in the binding capacity of 1-anilinonaphthalene-8-sulfonate to BSA. The binding of NY-S to BSA was diminished by the chemical modification of tryptophan residue in the BSA molecule with 2-hydroxy-5-nitrobenzyl bromide and o-nitrophenylsulfenyl chloride. The higher modifications rate of tryptophan residue decreased the binding constant of NY-S to BSA. These results suggest that the first binding site of NY-S to BSA is located in a hydrophobic area including tryptophan which is position 134 on the amino acid sequence of BSA. Studies on BSA modified with diethylpyrocarbonate demonstrated that a histidine residue also may participate in the binding of NY-S to BSA.
Subject(s)
Naphthalenesulfonates/blood , Serum Albumin, Bovine/metabolism , Animals , Binding Sites , Cattle , Chemical Phenomena , Chemistry , Dialysis , Kinetics , Protein Binding , Spectrometry, FluorescenceSubject(s)
Amaranth Dye/toxicity , Azo Compounds/toxicity , Naphthalenesulfonates/blood , Amaranth Dye/metabolism , Amniotic Fluid/metabolism , Animals , Biotransformation , Female , Fetal Blood/metabolism , Gestational Age , Male , Maternal-Fetal Exchange , Naphthalenesulfonates/metabolism , Pregnancy , Rats , Time FactorsABSTRACT
A simple, rapid, sensitive, and reproducible microdetermination of naphthionic acid (NA) in serum and amniotic fluid is described. The detection limit of the method is 1 ng NA in 20 microL serum, and 3 ng NA in 50 microL amniotic fluid. The concentration of nonderivatized NA was measured by fluorescence spectrophotometry (excitation 328 nm, emission 420 nm) of the supernate, after precipitation of proteins with absolute ethanol and heating for 30 min at 75 degrees C. Standard deviations of determinations for 2, 10, and 50 ng NA in 20 microL serum were 10.1, 7.59, and 7.64%, respectively. An analyst can perform about 100 determinations daily; results are available within 2 hr of sampling. A modification of the procedure to permit quantitation of NA in urine is also described.
