Information is needed on organic polyphosphates such as myo-inositol 1,2,3,5/4,6-hexakis dihydrogenphosphate or phytate (IP6) contribution to the sources and sinks of dissolved phosphorus (PO4-P) in the soil-manure-water system. Effects of Na+, Ca2+, Al3+, and Fe3+ and cation to IP6-P mole ratios on the enzymatic dephosphorylation of IP6 were studied to determine controlling mechanisms of dephosphorylation and persistence in manure. Phytate- and PO4-P were analyzed by high-performance liquid chromatography. Phytate dephosphorylation by Aspergillus ficuum (Reichardt) Henn. phytase EC 3.1.3.8 decreases by 50 +/- 3.6 and 40 +/- 4% at pH 4.5 and 6, respectively, as Ca2+ concentrations increase and cation to IP6-P mole ratios reach 6:6. Polyanionic IP6 has a high affinity for Al3+ and Fe3+ and reductions in dephosphorylation average 27 and 32% at a cation to IP6-P mole ratio of 1:6 for Al3+ and Fe3+, respectively, while reaching more than 99% at a mole ratio of 6:6. A phytase-hydrolyzable phosphorus (PHP) fraction is native to ruminant animal manure and is proportional to total solids (TS) concentration in 1 to 100 g L(-1) suspensions. Added phytase, in effect, increases water-extractable P content of manure and the risk of environmental P dispersion. As the bioavailability and ecological effect of IP6-P appear to be regulated not only by pH-controlled enzyme activity but also by the associated counterions, the differential protective effects of cations influence the accuracy of manure PHP fraction estimates and increase phytate resistance to enzymatic dephosphorylation that may lead to its persistence in manure.
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http://dx.doi.org/10.2134/jeq2003.6940 | DOI Listing |
Am J Cancer Res
December 2024
Department of Pharmacology and Toxicology, Medical College of Wisconsin Milwaukee, Wisconsin 53226, USA.
Cancer cell overexpresses numerus proteins, however, how these up-regulated proteins, especially those enzymatically opposite kinases and phosphatases, act together to promote oncogenesis is unknown. Here, we reported that protein tyrosine phosphatase H1 (PTPH1) is a scaffold protein for receptor tyrosine kinase (HER2) to potentiate breast tumorigenesis. PTPH1 utilizes its PDZ domain to bind HER2, p38γ, PBK, and YAP1 and to increase HER2 nuclear translocation, stemness, and oncogenesis.
View Article and Find Full Text PDFPlants (Basel)
December 2024
School of Advanced Engineering Studies, Institute of Biotechnology, Bioengineering and Food Systems, FEFU, 10 Ajax Bay, 690922 Vladivostok, Russia.
Alkaline phosphatase (ALP) of the PhoA family is an important enzyme in mammals, microalgae, and certain marine bacteria. It plays a crucial role in the dephosphorylation of lipopolysaccharides (LPS) and nucleotides, which overstimulate cell signaling pathways and cause tissue inflammation in animals and humans. Insufficient ALP activity and expression levels have been linked to various disorders.
View Article and Find Full Text PDFProtein Sci
January 2025
Department of Chemistry, Columbia University, New York, New York, USA.
The rapid identification of protein-protein interactions has been significantly enabled by mass spectrometry (MS) proteomics-based methods, including affinity purification-MS, crosslinking-MS, and proximity-labeling proteomics. While these methods can reveal networks of interacting proteins, they cannot reveal how specific protein-protein interactions alter protein function or cell signaling. For instance, when two proteins interact, there can be emergent signaling processes driven purely by the individual activities of those proteins being co-localized.
View Article and Find Full Text PDFChembiochem
December 2024
Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, 90095, United States.
While sugar-containing natural products are commonly biosynthesized via glycosyltranferases using sugar-UDP as the electrophile, nature has evolved alternative strategies of glyco-modification to expand the diversity of natural products. Hydroxyl groups on sugars can serve as nucleophiles in the release of polyketide products from polyketide synthases. Herein, we demonstrate a highly reducing polyketide synthase (HRPKS) from the biocontrol fungus Trichoderma afroharzianum T22, which is terminated with a carnitine acyltransferase (cAT) domain, catalyzes the biosynthesis of a d-galactose esterified polyketide named as trichogalactin.
View Article and Find Full Text PDFJ Chromatogr A
December 2024
KU Leuven - University of Leuven, Pharmaceutical Analysis, Department of Pharmaceutical and Pharmacological Sciences, O&N2, PB 923, Herestraat 49 3000 Leuven, Belgium. Electronic address:
Natural products (NPs) play an important role in drug discovery and drug development due to their diverse chemical properties and biological activities. In the present work, an on-line capillary electrophoresis (CE) method was developed and applied to screen protein tyrosine phosphatase 1B (PTP1B) inhibitors in NPs. As a generic technique, transverse diffusion of laminar flow profiles (TDLFP) was utilized to mix all reactants in the capillary for on-line enzymatic reaction.
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