Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.23 (beta-galactosidase)
14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Seven antisera raised against 11 alpha-hydroxyprogesterone 11-hemisuccinate (P11-HS) were used in microtitre plate enzymeimmunoassays (EIAs) for progesterone to identify improvements in sensitivity achievable by using various heterologous labels. EIAs using beta-galactosidase linked to P11-HS, 11 alpha-hydroxyprogesterone 11-hemimaleate (P11-HM), 11 alpha-hydroxyprogesterone 11-glucuronide (P11-Glu) or progesterone 3-(o-carboxymethyl) oxime (P3-CMO) were compared. Loss of sensitivity through bridge recognition was least evident using the P11-Glu derivative. The same seven antisera were used to evaluate assay sensitivity using beta-galactosidase, alkaline phosphatase, penicillinase and peroxidase linked to P11-HS or P11-Glu as label. Consistent improvements were achieved with the heterologous assays in the order penicillinase greater than alkaline phosphatase/peroxidase greater than beta-galactosidase: with penicillinase, sensitivity generally exceeded that of RIA. These data provide evidence for the general efficacy of the combination 11 alpha-hemisuccinate (immunogen bridge) and 11 alpha-glucuronide (label bridge) in reducing bridge recognition. EIA performed at 4 degrees C provided greater sensitivity than at ambient temperature (21 degrees C) or 40 degrees C, however, ambient temperature incubation provided a practical compromise. Equilibrium was not achieved under any of the conditions investigated.
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PMID:The influence of heterology, enzyme label and assay conditions on the sensitivity of microtitre plate enzymeimmunoassays for progesterone in milk. 255 Jul 5

A novel amplification system has been developed for the detection of free or antibody-conjugated alkaline phosphatase. The amplification system provides a 100 fold enhancement in the detection of the enzyme, compared to direct detection with chromogenic substrates. The key to the amplification system is the dephosphorylation of a potent phosphorylated inhibitor, and the visualization of this inhibitor using a second, indicator, reaction. This system is shown to provide increased sensitivity for immunoassays detecting either herpes simplex virus or respiratory syncytial virus in clinical samples. In addition, this general concept for amplification may be applicable to a variety of other hydrolytic enzymes, and is demonstrated for the enhanced detection of beta-galactosidase.
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PMID:The development of a novel immunoassay amplification system and its use in viral detection. 255 98

Milk samples (186) were obtained at various stages of lactation from 27 common brushtail possums (Trichosurus vulpecula). Qualitative and quantitative changes in the milk carbohydrates during early and mid-lactation were similar to those previously seen in other marsupials; the principal carbohydrate was lactose early in lactation and higher oligosaccharides in mid-lactation, and the hexose concentration reached a peak during mid-lactation. However, the late-lactation milk was unusual in that the carbohydrate was mainly lactose and its concentration remained relatively high (3.5 to 5.5%). In contrast to earlier findings on the milk of the tammar wallaby (Macropus eugenii), little or no nucleotide pyrophosphatase, beta-galactosidase and alkaline phosphatase activities were detected late in lactation.
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PMID:Changes in milk carbohydrates during lactation in the common brushtail possum, Trichosurus vulpecula (Marsupialia:Phalangeridae). 256 94

Male Sprague-Dawley rats were challenged with various hyperoxaluric agents including ammonium oxalate, hydroxy-L-proline, and ethylene glycol. All treatments resulted in increased urinary oxalate. Associated with hyperoxaluria was an increase in urinary levels of renal enzymes, gamma-glutamyl transpeptidase, N-acetyl-beta-glucosaminidase, and alkaline phosphatase. Most of the rats did not demonstrate any significant change in urinary levels of beta-galactosidase. There was a highly significant positive correlation between urinary oxalate and N-acetyl-beta-glucosaminidase.
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PMID:Urinary enzymes and calcium oxalate urolithiasis. 257 Jan 67

The sensitivities of monoclonal antibody-based enzyme immunoassays for 11-deoxycortisol using alkaline phosphatase (AP), horseradish peroxidase (HRP), beta-galactosidase (beta-GAL) and glucose oxidase (GOD) as labels were compared. The anti-11-deoxycortisol antibody used was that produced in ascites by inoculating antibody-secreting hybridoma cells into mice. Enzyme labeling of 11-deoxycortisol was carried out by the N-succinimidyl ester method. The activated ester of 4-(2-carboxyethylthio)-11-deoxycortisol was treated with each enzyme to give a homologous enzyme-labeled antigen. In the competitive immunoassay, the bound and free enzyme-labeled antigens were separated by a double antibody method and the enzymic activity of the immune precipitate was determined by colorimetric and fluorimetric methods. The AP activity was measured in three ways, using p-nitrophenyl phosphate, nicotinamide adenine dinucleotide phosphate (NADP), and 4-methylumbelliferyl phosphate as substrates. o-Nitrophenyl beta-D-galactopyranoside and 4-methylumbelliferyl beta-D-galactopyranoside were used for beta-GAL, and 3,3',5,5'-tetramethylbenzidine (TMB) and 3-(p-hydroxyphenyl)propionic acid (HPPA) for HRP. In the case of GOD, TMB and HPPA were used in combination with HRP. A dose-response curve with a high sensitivity was obtained in each 11-deoxycortisol assay system by the use of a minimum amount of the enzyme-labeled antigen at an appropriate dilution of monoclonal anti-11-deoxycortisol antibody (Ka = 2 x 10(10) M-1). The amounts of 11-deoxycortisol needed to displace 50% of the bound label ranged from 5 to 15 pg in the colorimetric methods, and 4-9 pg in the fluorimetric methods.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Sensitivity of steroid enzyme immunoassays. Comparison of four label enzymes in an assay system using a monoclonal anti-steroid antibody. 268 Jan 24

Reaction rates in metabolic pathways typically exhibit a kind of diminishing returns in which small variations in the activities of the individual enzymes have very little effect on overall flux. These effects are measured by the control coefficients of the enzymes, and most systems are governed by the summation theorem stating that all control coefficients must sum to unity. One implication is that complex systems will not usually contain single rate limiting steps, but rather be controlled to a greater or lesser extent by many enzymes, each exerting relatively small control. Wright understood this principle in 1934 and used it for his physiological theory of dominance. With respect to small variations in enzyme activity, the principle implies that many small variations should have only mild effects on fitness. Analysis of nucleotide polymorphisms in the genes for glucose-6-phosphate dehydrogenase and alkaline phosphatase in Escherichia coli implies that most amino acid replacements are harmful, and that the average selection coefficient against amino acid replacements that are polymorphic in natural populations is 1 x 10(-7) to 5 x 10(-7). In experiments to determine the a priori distribution of selection coefficients among random amino acid replacements, 25 replacements in beta-galactosidase were created by genetic means, and 22 of these produced selective effects too small to be detected in chemostat competition experiments (s less than 0.004 per generation).
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PMID:The physiology of weak selection. 268 89

The Tsr protein of Escherichia coli is a chemosensory transducer that mediates taxis toward serine and away from certain repellents. Like other bacterial transducers, Tsr spans the cytoplasmic membrane twice, forming a periplasmic domain of about 150 amino acids and a cytoplasmic domain of about 300 amino acids. The 32 N-terminal amino acids of Tsr resemble the consensus signal sequence of secreted proteins, but they are not removed from the mature protein. To investigate the function of this N-terminal sequence in the assembly process, we isolated translational fusions between tsr and the phoA and lacZ genes, which code for the periplasmic enzyme alkaline phosphatase and the cytoplasmic enzyme beta-galactosidase, respectively. All tsr-phoA fusions isolated code for proteins whose fusion joints are within the periplasmic loop of Tsr, and all of these hybrid proteins have high alkaline phosphatase activity. The most N-terminal fusion joint is at amino acid 19 of Tsr. Tsr-lacZ fusions were found throughout the tsr gene. The beta-galactosidase activity of the LacZ-fusion proteins varies greatly, depending on the location of the fusion joint. Fusions with low activity have fusion joints within the periplasmic loop of Tsr. The expression of these fusions is most likely reduced at the level of translation. In addition, one of these fusions markedly reduces the export and processing of the periplasmic maltose-binding protein and the outer membrane protein OmpA, but not of intact PhoA or of the outer membrane protein LamB. A temperature-sensitive secA mutation, causing defective protein secretion, stops expression of new alkaline phosphatase activity coded by a tsr-phoA fusion upon shifting to the nonpermissive temperature. The same secA mutation, even at the permissive temperature, increases the activity and the level of expression of LacZ fused to the periplasmic loop of Tsr relative to a secA+ strain. We conclude that the assembly of Tsr into the cytoplasmic membrane is mediated by the machinery responsible for the secretion of a subset of periplasmic and outer membrane proteins. Moreover, assembly of the Tsr protein seems to be closely coupled to its synthesis.
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PMID:The Tsr chemosensory transducer of Escherichia coli assembles into the cytoplasmic membrane via a SecA-dependent process. 284 45

A transposon Tn917 insertion between gerE and ilvB has identified a new developmental locus, gerM, in Bacillus subtilis. gerM96::Tn917 affects both sporulation and germination. DNA on either side of the transposon has been cloned and includes the previously cloned sdhC and gerE loci. gerE terminates 2.1 kb from the end of the transposon. The gerM96::Tn917 mutant is oligosporogenous, yielding approximately 1% of the number of wild-type heat resistant spores in liquid medium and 10% on solid medium. Six hours after the onset of sporulation alkaline phosphatase and glucose dehydrogenase levels were 90% and 7%, respectively, of those of the wild-type. At this time 50% of the mutant cells were still dividing. The occurrence of multiple polar septa and 'pygmy' cells suggested a block at stage II of sporulation. Following addition of germinants, mutant spores prepared on nutrient agar lost heat resistance normally but released slightly less dipicolinic acid than wild-type spores. They also showed only partial loss of optical density, associated with a phase-grey appearance and striations in the cortex suggesting partial degradation. Expression of the gerM gene was monitored by production of beta-galactosidase encoded by a promotorless lacZ gene fused to the gerM96::Tn917 insertion. It occurred 1.5-4 h after commencement of sporulation. Transcription was directed from a promoter on the gerE side of gerM and was unaffected by a mutation in the gerE gene.
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PMID:Genetical and molecular studies on gerM, a new developmental locus of Bacillus subtilis. 284 48

alpha-Lactalbumin was isolated from milk of M. eugenii and its concentration in milk samples taken at various times during lactation (0-40 weeks post partum) was determined by single radial immunodiffusion using rabbit antiserum to the purified protein. The alpha-lactalbumin concentration remained almost constant throughout lactation even though the concentration of total lactose (free lactose plus lactose contained in oligosaccharides) fell to zero after 34 weeks post partum. This fall in lactose was accompanied by a rise in the free galactose and glucose concentrations and marked increases in UDP-galactose hydrolase, nucleotide pyrophosphatase, alkaline phosphatase and acid beta-galactosidase activities. It is suggested that the in vitro hydrolysis of UDP-galactose was due to nucleotide pyrophosphatase and that this enzyme may also play a role in vivo late in lactation by making UDP-galactose unavailable for the synthesis of lactose. Alternatively, lactose and lactose-containing oligosaccharides might be degraded by the acid beta-galactosidase during or after secretion.
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PMID:Changes in alpha-lactalbumin, total lactose, UDP-galactose hydrolase and other factors in tammar wallaby (Macropus eugenii) milk during lactation. 285 90

We have treated bovine lung heparan sulfate with alkaline [3H]borohydride to end label the chains with [3H]xylitol. After subsequent periodate oxidation-alkaline elimination products were separated by gel permeation and ion exchange chromatography. The linkage region fragment expected to have 2 galactoses and 1 [3H]xylitol residue appeared in the tetra-/trisaccharide region after gel filtration and was bound to the anion exchange resin. A similar negatively charged fragment, expected to have 2 galactoses, 1 xylose and 1 serine, was isolated after periodate oxidation-alkaline elimination of unlabeled heparan sulfate. The negative charge was due to the presence of alkaline phosphatase-labile phosphate ester. The molar ratio of galactose:phosphate:xylose was 2.17:1.19:1.00. The phosphate ester was associated with the xylose/[3H] xylitol moiety as indicated by the formation of phosphoxylose/-xylitol by beta-galactosidase digestion of the phosphorylated trisaccharide. Furthermore, orcinol reactivity disappeared after periodate oxidation of the dephosphorylated trisaccharide. The phosphate ester must be located to C-2 of xylose/xylitol as the 1-3H radioactivity could be released by periodate oxidation when it was preceded by alkaline phosphatase treatment. It is estimated that almost every chain of heparan sulfate carries 2-phosphoxylose. It would be of interest to know if glycosaminoglycan chains that are artificially initiated onto exogeneous beta-D-xylosides also acquire the 2-phosphoxylose moiety.
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PMID:Structure of the heparan sulfate-protein linkage region. Demonstration of the sequence galactosyl-galactosyl-xylose-2-phosphate. 293 48


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