1.O-phospho-L-serine: a modulator of bone healing in calcium-phosphate cements.
Mai R1, Lux R, Proff P, Lauer G, Pradel W, Leonhardt H, Reinstorf A, Gelinsky M, Jung R, Eckelt U, Gedrange T, Stadlinger B. Biomed Tech (Berl). 2008 Oct;53(5):229-33. doi: 10.1515/BMT.2008.040.
Bone substitution materials are seen as an alternative to autogenous bone transplants in the reconstruction of human bone structures. The aim of the present animal study was to evaluate the clinical handling and the conditions of bone healing after the application of a phosphoserine and collagen-I-modified calcium-phosphate cement (Biozement D). The application of phosphoserine is supposed to influence the texture of the extracellular matrix. Standardised bone defects were created in the lower jaw of 10 adult minipigs. These defects were reconstructed with a pasty calcium-phosphate cement mixture. After a healing time of 4 months, the animals were sacrificed. The mandibles of all animals were resected and non-decalcified histological sections of the areas of interest were prepared. The experiment was evaluated by means of qualitative histology and histomorphometry. The hydroxyapatite cement entirely hardened intraoperatively. Modelling and handling of the cement was facile and the margin fit to the host bone was excellent.
2.Analysis of L-serine-O-phosphate in cerebrospinal spinal fluid by derivatization-liquid chromatography/mass spectrometry.
McNaney CA1, Benitex Y2, Luchetti D3, Labasi JM3, Olah TV4, Morgan DG2, Drexler DM5. Anal Biochem. 2014 May 1;452:10-2. doi: 10.1016/j.ab.2014.02.007. Epub 2014 Feb 15.
L-serine-O-phosphate (L-SOP), the precursor of L-serine, is a potent agonist against the group III metabotropic glutamate receptors (mGluRs) and, thus, is of interest as a potential biomarker for monitoring modulation of neurotransmitter release. So far, no reports are available on the analysis of L-SOP in cerebrospinal fluid (CSF). Here a novel method is presented to determine L-SOP levels in CSF employing precolumn derivatization with (5-N-succinimidoxy-5-oxopentyl)triphenylphosphonium bromide (SPTPP) coupled to liquid chromatography/mass spectrometry (derivatization-LC/MS, d-LC/MS).
3.Epigallocatechin-3-gallate and penta-O-galloyl-β-D-glucose inhibit protein phosphatase-1.
Kiss A1, Bécsi B, Kolozsvári B, Komáromi I, Kövér KE, Erdődi F. FEBS J. 2013 Jan;280(2):612-26. doi: 10.1111/j.1742-4658.2012.08498.x. Epub 2012 Feb 13.
Protein phosphatase-1 (PP1) and protein phosphatase-2A (PP2A) are responsible for the dephosphorylation of the majority of phosphoserine/threonine residues in cells. In this study, we show that (-)-epigallocatechin-3-gallate (EGCG) and 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG), polyphenolic constituents of green tea and tannins, inhibit the activity of the PP1 recombinant δ-isoform of the PP1 catalytic subunit and the native PP1 catalytic subunit (PP1c) with IC(50) values of 0.47-1.35 μm and 0.26-0.4 μm, respectively. EGCG and PGG inhibit PP2Ac less potently, with IC(50) values of 15 and 6.6 μm, respectively. The structure-inhibitory potency relationships of catechin derivatives suggests that the galloyl group may play a major role in phosphatase inhibition. The interaction of EGCG and PGG with PP1c was characterized by NMR and surface plasmon resonance-based binding techniques. Competitive binding assays and molecular modeling suggest that EGCG docks at the hydrophobic groove close to the catalytic center of PP1c, partially overlapping with the binding surface of microcystin-LR or okadaic acid.
