Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.11.1.7 (peroxidase)
 65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Stabilizers added to preparations of human serum albumin before heat treatment were tested for bilirubin displacing effect, using the peroxidase method. It was found that N-acetyltryptophan and sodium caprylate displace bilirubin from its complex with human serum albumin in vitro. The quantitative findings were used for a rough estimate of the effect of these substances on the free bilirubin concentration in blood plasma, expected when stabilized albumin preparations are given intravenously for prevention of kernicterus. The calculated effect is a delay of the decrease of free bilirubin concentration, or even a temporary increase. Sodium mandelate displaces less strongly.
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PMID:Bilirubin displacing effect of stabilizers added to injectable preparations of human serum albumin. 55 76

Drugs which compete with bilirubin for albumin binding may increase the risk of kernicterus. Fortunately, few drugs are strong competitors. However, in neonatology, many drugs are used simultaneously. We have studied the effect of drug combinations on bilirubin binding using human serum albumin and the peroxidase method. Combinations of aminophylline with phenobarbital, cefotaxime and vancomycin were studied as well as the combination of vancomycin and cefotaxime. The results show that the bilirubin-displacing effect of the drug combinations cannot be predicted from each drug's individual effect. These results are consistent with a flexible model of albumin binding. Combinations of drugs which are both albumin-bound and reach high serum concentrations should be tested for their combined effect on bilirubin binding and this information used in deciding on treatment in sick, premature infants.
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PMID:Effect of drug combinations on bilirubin-albumin binding. 181 27

Twenty-eight drugs, including cephem antibiotics and anti-inflammatory agents currently used or considered potentially useful in neonatal intensive care nurseries in Japan, were examined to determine their influence on albumin and bilirubin interaction by means of a glucose oxidase - peroxidase method, using an automated analyzer (Arrows) for unbound bilirubin (U.B.). The apparent binding constant for drugs to the high-affinity site on albumin (KD) was determined. Of cephem antibiotics, latamoxef sodium (LMOX) and cefazolin sodium (CEZ) were found to displace bilirubin from albumin (KD = 5.9 x 10(3) M-1 and 4.5 x 10(3) M-1, respectively) as strongly as Na salicylate (KD = 6.8 x 10(3) M-1). Mephenamate and indomethacin, which are used for medical closure of patent ductus arteriosus in premature infants, were also found to be stronger bilirubin displacers (KD = 1.3 x 10(5) M-1 and 1.2 x 10(5) M-1, respectively) than sulfisoxazole (KD = 1.6 x 10(4) M-1). Maximal displacement factors (MDF's) were also estimated in reference to protein binding (%) and effective serum concentration (M) of each drug in human adults. Of these drugs, mephenamate showed a higher risk of bilirubin displacement (MDF = 3.79) than sulfisoxazole (MDF = 2.58) and LMOX had a higher risk of displacement (MDF = 1.97) than Na salicylate (MDF = 1.85). On the other hand, indomethacin and CEZ showed minimal effects on displacement at therapeutic levels (MDF = 1.03 and 1.00, respectively). At therapeutic serum levels, mephenamate and LMOX may possess the potential for displacing bilirubin from albumin and increasing the risk of bilirubin encephalopathy, in a manner similar to sulfisoxazole.
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PMID:Influence of drugs on albumin and bilirubin interaction. 250 25

Ceftriaxone, a cephalosporin, is bound reversibly to defatted human serum albumin from adults, with a first stoichiometric binding constant of 60,000 M-1, as found by equilibrium dialysis at pH 7.4, 37 degrees. A second molecule is weakly bound, with a binding constant of 500 M-1. Possible cobinding with bilirubin was studied by the peroxidase method and by equilibrium dialysis with and without added bilirubin. Results indicated competitive binding; formation of an albumin complex containing both bilirubin and ceftriaxone could not be demonstrated. Light absorption spectra of bilirubin-albumin showed little change on addition of ceftriaxone, in agreement with the competitive biding mechanism. Binding to serum albumin from newborn infants is weaker than to the protein from adults, with the first binding constant being about 36,000 M-1. Cobinding of ceftriaxone and bilirubin to albumin from newborn infants is likewise competitive. It is concluded that ceftriaxone is a strong bilirubin displacer with a potential of inducing bilirubin encephalopathy in predisposed newborns.
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PMID:Ceftriaxone binding to human serum albumin: competition with bilirubin. 277 27

The effect of parenterally administered cephalosporins on bilirubin-albumin binding was measured in vitro by means of the peroxidase method with human serum albumin and by means of a dialysis rate method with newborn infants' serum. Ceftriaxone and cefoperazone have been shown to affect bilirubin-albumin binding. In this study, 13 additional cephalosporins were tested. Cefonicid, cefotetan, and cefmetazole competed with bilirubin for albumin binding and, at reported mean peak serum levels, decreased the reserve albumin concentration by 75%, 56%, and 40%, respectively. We suggest that these five cephalosporins may increase the risk of bilirubin encephalopathy in jaundiced neonates.
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PMID:Effect of cephalosporins on bilirubin-albumin binding. 333 10

Unbound bilirubin is oxidized to nearly colourless substances in the presence of H2O2 or ethyl hydroperoxide and horseradish peroxidase. To predict the risk of kernicterus (degenerated yellow pigmentation of nerve cells), this principle has been widely utilized for estimating the concentration of unbound bilirubin in hyperbilirubinaemic serum. However, the serum contains polar geometric photoisomers of bilirubin. Therefore, to clarify the effect of bilirubin photoisomer concentrations on unbound-bilirubin concentration, the concentration of bilirubin and its photoisomer and of unbound bilirubin in samples obtained from experiments in vivo and in vitro were simultaneously and individually estimated by h.p.l.c. and the peroxidase method. During photoirradiation, both in vivo and in vitro, the serum polar (ZE)-bilirubin IX alpha concentration increased remarkably, but unbound-bilirubin values were not affected at all. However, during experiments in vitro, unbound bilirubin concentrations increased only when concentrations of the rather polar (EZ)- and (EE)-cyclobilirubin IX alpha increased considerably in a human serum albumin-bilirubin solution irradiated with blue light. Thus it is concluded that unbound-bilirubin concentrations, and consequently the initial rate of the peroxidase reaction, is not accelerated by the increase in either (ZE)-bilirubin or (EZ)-cyclobilirubin concentration within the clinically observed range.
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PMID:The effect of bilirubin photoisomers on unbound-bilirubin concentrations estimated by the peroxidase method. 354 81

The effect of ceftriaxone on bilirubin-albumin binding was measured in vitro using the peroxidase method with human serum albumin and a dialysis rate method with adult and newborn serum. Ceftriaxone competes with bilirubin for binding to human serum albumin; the displacement constant is 1.5 X 10(4) L/mol. Therapeutic levels of ceftriaxone decrease the reserve albumin concentration in newborn serum by 39%. These results indicate that ceftriaxone may increase the risk of bilirubin encephalopathy in jaundiced premature infants.
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PMID:Ceftriaxone effect on bilirubin-albumin binding. 368 99

Bumetanide binding to human serum albumin was studied using ultrafiltration. The first stoichiometric binding constant for bumetanide is 6.4 X 10(4) M-1. Bumetanide competes with bilirubin for human serum albumin binding, having a KDispl (displacement constant) of 6.2 X 10(3) M-1 measured by the peroxidase method. This displacement effect is also observed using pooled umbilical cord serum and pooled adult serum employing a dialysis rate method. Bumetanide competes to a lesser degree with diazepam binding to human serum albumin. No competition with diazepam occurs using umbilical cord or adult serum. Pharmacologic concentrations of bumetanide would not significantly affect bilirubin-albumin binding and should not increase the risk of bilirubin encephalopathy in newborn infants.
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PMID:Albumin binding of bumetanide. 375 31

Essential differences are demonstrated between bilirubin binding to rat serum proteins and to albumin in human serum. Acidimetric titration of rat serum with and without added bilirubin shows that binding of bilirubin acid in the range of pH from 6.8 to 8.8 takes place with release of less than one hydrogen ion per molecule of bound bilirubin. With human serum, two hydrogen ions are released, indicating binding of bilirubin dianion. The binding equilibrium of N-[4-[(4-aminophenyl)-sulfonyl]phenyl]-acetamide (MADDS) to rat serum albumin is influenced slightly by cobinding of bilirubin whereas MADDS and bilirubin bind competitively to human serum albumin. Finally, the rate of oxidation of bilirubin with hydrogen peroxide and peroxidase is decreased moderately by addition of rat serum albumin and strongly by the human protein, indicating that biliribin in its complex with rat serum albumin is subject to oxidation while the complex with human serum albumin is protected. These differences should be considered when rats are used as a model in experimental studies aiming at prevention of bilirubin encephalopathy in human neonates.
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PMID:Bilirubin/rat serum albumin interaction. 396 51

In jaundiced newborn infants, hemolytic disease is considered a risk factor for kernicterus due to the suspected competition between bilirubin and other hemoglobin breakdown products for albumin binding. We have studied the effect of hematin on bilirubin-albumin binding using the peroxidase assay and a light-scattering technique for measuring unbound bilirubin. Our results show that hematin does not affect bilirubin-albumin binding. To determine if other albumin binding functions are affected by hematin, we used a microdialysis rate technique employing two ligands, diazepam and monoacetyldiaminodiphenyl sulfone (MADDS). Hematin does not utilize the diazepam binding function of albumin, but does decrease the albumin binding of MADDS. The results of this study indicate that the MADDS and bilirubin binding functions are not identical. The clinical usefulness of reserve albumin equivalent determination using MADDS is discussed.
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PMID:Hematin and bilirubin binding to human serum albumin and newborn serum. 400 60


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