SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Diamine oxidase present in the cotyledons of germinating pea seeds is induced by phytic acid but the embryo enzyme is not affected. Polyamines have no effect on phytase activity of the cotyledon or embryo.
Phytic acid exerts a significant antinutritional effect in poultry, swine, and fish, which can be mitigated by supplementing monogastric feeds with efficient microbial phytases. Accordingly, mining bacterial genomes for novel phytases represents a strategic computational approach to identifying candidates for improving monogastric animal nutrition. In this study, 162 bacterial genomes associated with horse feces were systematically mined using an in silico pipeline to identify and characterize putative phytases.A total of 69 non-redundant sequences were identified and classified as histidine acid phytase (HAPhy) or protein tyrosine phosphatase-like phytase (PTPLPhy). HAPhys were detected in the genomes of Escherichia coli, Klebsiella pneumoniae, Salmonella enterica, Acinetobacter baumannii, and Cutibacterium equinum, whereas PTPLPhys were found in K. pneumoniae, Limosilactobacillus reuteri, Pediococcus acidilactici, Bifidobacterium pseudolongum, and Prescottella equi. Principal component analysis identified glucose-1-phosphatase (CAJ1242485.1) and bifunctional acid phosphatase (NHR17779.1) as the HAPhy candidates exhibiting the most favorable predicted physicochemical properties for potential feed applications. Similarly, among the PTPLPhys, protein tyrosine phosphatase (UNQ40438.1) and a hypothetical protein (CAJ1246072.1) showed the most favorable computational profiles. Biosafety analysis identified potential virulence factors, indicating that sources should be screened prior to feed application. High-quality AlphaFold2 models were obtained for these phytases (90.9-97.2). Molecular docking analysis showed that NHR17779.1 exhibited the strongest binding to phytic acid, whereas CAJ1246072.1 demonstrated the weakest interaction. Overall, this study identifies the horse fecal microbiota as a diverse source of putative phytases that may serve as promising targets for genetic and protein engineering; however, further in vitro and in vivo studies are essential to validate the enzymatic activity and industrial efficacy of these computational candidates.
1. Kinetic data for avian erythrocyte AMP-deaminase in lysate supernatants and 2000-fold purified enzyme were consistent with an allosteric model having four binding sites for substrate. 2. Relative to the purified enzyme, AMP-deaminase in lysate supernatants exhibited a greater S0.5 and enhanced sensitivity toward phytic acid, but was far less sensitive toward potassium ion. 3. In the absence of potassium chloride, the enzymatic activity in lysates exhibited hysteresis at subsaturating 5'-AMP. This response was modified reversibly by allosteric ligands. 4. It is concluded that the characteristics of avian RBC AMP-deaminase, as expressed in lysates, may reflect important intermolecular interactions and better represent the regulatory properties of this enzyme in erythrocytes.
1. A study has been made of the zinc, copper, iron, manganese, protein (nitrogen X 6.25) and phytic acid contents of nineteen soya-bean-based textured-vegetable-protein (TVP) meat-extenders and meat-substitutes and of three "ready-prepared" canned meals containing TVP. 2. Phytate analysis was performed using a newly-developed method based on Holt's (1955) procedure. This method enabled the phytate content of milligram quantities of TVP to be estimated, with an SD for six replicates of 3%. 3. The Fe, Cu and Mn contents (mg/kg) of the meat extenders or meat-substitutes varied, with values of 59.4-144, 14.1-19.7 and 19.5-29.1 respectively. The protein content of these products was approximately 500 g/kg. 4. The phytate content of the meat-extenders and meat-substitutes ranged from 11.0 to 20.2 g/kg and the Zn content from 35.0 to 49.4 mg Zn/kg. The calculated molar ratio, phytate: Zn varied from 25 to 42. 5. The trace element, phytate and protein contents of the "ready-prepared" canned meals were 30-50% lower than the meat-extenders and meat-substitutes. 6. Cooking the "ready-prepared" meals as specified by the manufacturers was without effect on the trace element or phytate content. 7. When TVP was fed to rats as the only protein source, they had significantly lower growth rates and plasma Zn concentrations than rats given an egg-albumen-based diet of similar Zn content (14.5 mg Zn/kg). Supplementation of the TVP diet with Zn (100 mg Zn/kg) significantly increased growth rate and plasma Zn concentration whereas Zn supplementation of the albumen diet was without effect. 8. The possible implications of consumption of TVP products in relation to Zn status of the human population is discussed.
The influence of various salts, chelates, and other complexes of zinc given by gavage on serum zinc levels in rats was studied. Serum zinc concentrations were determined over 6 hr after administration of zinc sulfate at doses of 5, 10, 20, 50, and 100 mg of zinc/kg. Serum zinc levels following doses of zinc salts and complexes were compared with those after zinc sulfate. Phytic acid, aminopolycarboxylic acids (including edetate disodium), and penicillamine significantly suppressed increases in serum zinc concentration. Some natural amino acid-zinc sulfate mixtures (those with lysine, cysteine, glycine, and histidine) produced greater levels than the equivalent dose of zinc sulfate alone. Several thiocarboxylic acids, such as mercaptoacetic acid and thiosalicylic acid, also increased serum zinc concentrations. These observations form a basis for attempted modification of zinc absorption in other species.
Explore the source record for details and available documents.
The binding of diphtheria toxin to 125I-labeled cell surface glycoproteins from hamster thymocytes was shown to be inhibited by nucleotides. The relative effectiveness of the nucleotides (at 5 mM) was found to be thymidine triphosphate greater than adenosine triphosphate greater than guanosine triphosphate greater than uridine triphosphate greater than cytidine triphosphate. When adenine-containing compounds were used, the relative effectiveness was determined to be adenosine tetraphosphate greater than adenosine triphosphate greater than adenosine diphosphate greater than adenosine monophosphate. In addition, tetrapolyphosphate, tripolyphosphate, inositol hexaphosphate (phytic acid), and the highly phosphorylated proteins casein and phosvitin were also shown to be potent inhibitors of the binding of diphtheria toxin to 125I-labeled cell surface glycoproteins. Diphtheria toxin was shown to bind directly to 125I-casein; this binding was also inhibited by the highly phosphorylated compounds and was decreased by pretreatment of the 125I-casein with alkaline phosphatase. These results suggest that diphtheria toxin binds to regions of high phosphate density and raise the possibility that the site on the cell surface glycoproteins to which diphtheria toxin binds might be polyanionic in nature.
A patient evaluated for heart failure was found by routine radionuclide angiography to have a large internal iliac arteriovenous fistula of presumed postoperative origin. The value of radionuclide angiography is described with a review of the literature on such unusual cases.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
1. Oxygen dissociation curves have been measured for human haemoglobin solutions with different concentrations of the allosteric effectors 2,3-diphosphoglycerate, adenosine triphosphate and inositol hexaphosphate. 2. Each effector produces a concentration dependent right shift of the oxygen dissociation curve, but a point is reached where the shift is maximal and increasing the effector concentration has no further effect. 3. Mathematical models based on the Monod, Wyman & Changeux (1965) treatment of allosteric proteins have been fitted to the data. For each compound the simple two-state model and its extension to take account of subunit inequivalence were shown to be inadequate, and a better fit was obtained by allowing the effector to lower the oxygen affinity of the deoxy conformational state as well as binding preferentially to this conformation.
Explore the source record for details and available documents.
The effect of oxygen-linked tetramer-dimer dissociation on oxygen equilibrium of hemoglobin was investigated by measuring the equilibrium curves over a wide range of protein concentration. A Hill scheme which takes the subunit dissociation into account describes well the overall concentration dependences of the oxygen pressure and slope of the Hill plot at half saturation. Values of dissociation constant for oxyhemoglobin estimated from the equilibrium data agree with the vaues measured by other methods for phosphate-free and diphosphoglycerate-added hemoglobin. The present results indicate that oxygen equilibrium properties are only slightly influenced bysubunit dissociation in the concentration range above 60 muM (as heme) at which most equilibrium experiments have been carried out.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.