Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It was the aim of this study to establish triglyceride matrices as potential carriers for long-term release of brain-derived neurotrophic factor (BDNF), a potential therapeutic for Huntington's disease. First, four different manufacturing strategies were investigated with lysozyme as a model substance: either lyophilized protein was mixed with lipid powder, or suspended in organic solution thereof (s/o). Or else, an aqueous protein solution was dispersed by w/o emulsion in organic lipid solution. Alternatively, a PEG co-lyophilization was performed prior to dispersing solid protein microparticles in organic lipid solution. After removal of the solvent(s), the resulting powder formulations were compressed at 250 N to form mini-cylinders of 2 mm diameter, 2.2 mm height and 7 mg weight. Protein integrity after formulation and release was evaluated from an enzyme activity assay and SDS-PAGE. Confocal microscopy revealed that the resulting distribution of FITC-lysozyme within the matrices depended strongly on the manufacturing method, which had an important impact on matrix performance: matrices with a very fine and homogeneous protein distribution (PEG co-lyophilization) continually released protein for 2 months. The other methods did not guarantee a homogeneous distribution and either failed in sustaining release for more than 1 week (powder mixture), completely liberating the loading (s/o dispersion) or preserving protein activity during manufacturing (w/o emulsion, formation of aggregates and 25% activity loss). Based on these results, miniature-sized implants of 1 mm diameter, 0.8 mm height and 1 mg weight were successfully loaded by the PEG co-lyophilization method with 2% BDNF and 2% PEG. Release studies in phosphate buffer pH 7.4 at 4 and 37 degrees C revealed a controlled release of either 20 or 60% intact protein over one month as determined by ELISA. SDS-PAGE detected only minor aggregates in the matrix during release at higher temperature. In vivo evaluation of lipid cylinders in the striatum of rat brains revealed a biocompatibility comparable to silicone reference cylinders.
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PMID:Towards controlled release of BDNF--manufacturing strategies for protein-loaded lipid implants and biocompatibility evaluation in the brain. 1742 70

It was shown in previous work that the interaction of growth factors (GFs) with adenosine triphosphate (ATP) is essential for their neuroprotective effect. Here we investigated the nature of the association of human basic fibroblast growth factor (bFGF), nerve growth factor (NGF), and brain-derived neurotrophic factor (BDNF) with ATP. It was demonstrated that this interaction involves the formation of non-covalent ATP-GF complexes that are labile at low pH and that could be selectively purified and subjected to electrospray and MALDI-TOF mass spectrometry. The results obtained with these techniques indicated that the stability of the complexes is high. Main features of the procedure used here are: (1) reversed-phase purification of nucleotide-protein non-covalent complexes, (2) their detection with MALDI-TOF-MS using acid-free matrix, and/or (3) their measurement with ESI-MS using soft desolvation conditions. The methodology was successful in providing proof for the presence of various nucleotide-GF complexes. It was extended to other nucleotide-binding proteins (ribonuclease A) as well as proteins that do not exhibit nucleotide binding (lysozyme) as positive and negative control, respectively. Thus, the method demonstrated its general use for the investigation of a wide range of proteins interacting with nucleotides as long as their complexes are sufficiently stable to accommodate the experimental conditions.
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PMID:Detection of ATP-binding to growth factors. 1805 12

We report the preparation of polymer capsules containing liposomal subcompartments, termed capsosomes, and their ability for the sustained delivery of protein therapeutics. Capsosomes were formed through the layer-by-layer (LbL) assembly of polymers and protein-loaded liposomes, followed by the formation of a capsule membrane based on disulfide cross-linked poly(methacrylic acid). The loading capacities of a model cargo (lysozyme) and brain-derived neurotrophic factor (BDNF), an important neurotrophin that has significant physiological functions on the nervous system, were determined, and the long-term release kinetics of the proteins was investigated in simulated physiological conditions. The capsosomes exhibited protein loading and release behavior that can be tuned by the lipid composition of the liposomal compartments, where inclusion of anionic lipids resulted in enhanced protein loading and slower release over the course of 80 days. These findings highlight the potential of capsosomes for the long-term delivery of protein therapeutics.
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PMID:Capsosomes as Long-Term Delivery Vehicles for Protein Therapeutics. 2615 47

Thermosensitive liposomes are clinically-relevant nanocarriers which have been used to deliver chemotherapeutic agents to tumors in combination with local hyperthermia. However, the encapsulation and release of macromolecular therapeutic agents (proteins, nucleic acids, bioactive polymers) is often hindered by their instability during the liposome formation as well as by the low encapsulation efficiency. The objective of this study was to investigate the influence of the thermosensitive liposomal formulation on the encapsulation and release of low and high molecular weight hydrophilic drugs, in order to identify the key parameters to control during nanocarrier design, depending on the specific drug delivery application. Thermosensitive liposomes with different formulations were prepared through the combinations of different lipids, including dipalmitoylphosphatidylcholine (DPPC), distearoylphosphatidylcholine (DSPC), cholesterol (Chol), 1-palmitoyl-2-hydroxy-sn-glycero-3-phosphocholine (P-Lyso-PC), and the PEGylated lipid distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxy(PEG)-2000 (DSPE-PEG2000). The thin film hydration method was used for liposome preparation and loading of different water soluble molecules. The encapsulation efficiency and release profiles were investigated for a low molecular weight compound such as carboxyfluorescein (CF), proteins (albumin), and hydrophilic polymers which do not interact with the lipid bilayer, such as a linear dextran and a poly(ethylene glycol)-based star polymer. An optimised liposomal formulation [DPPC/P-lyso-PC/DSPE-PEG2000 90/10/4 (mol/mol) (LTSL)] was chosen for further application in encapsulating therapeutic proteins, such as lysozyme and the brain-derived neurotrophic factor (BDNF), which are recognized as drug carriers and potential therapeutic agents for kidney diseases and neurological disorders.
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PMID:The effect of thermosensitive liposomal formulations on loading and release of high molecular weight biomolecules. 2837 18