Threonine aldolases catalyze the aldol condensation of aldehydes with glycine to furnish β-hydroxy-α-amino acid with two stereogenic centers in a single reaction. This is one of the most promising green methods for the synthesis of optically pure β-hydroxy-α-amino acid with high atomic economy and less negative environmental impact. Several threonine aldolases from different origins have been identified and characterized. The insufficient -carbon stereoselectivity and the challenges of balancing kinetic versus thermodynamic control to achieve the optimal optical purity and yield hampered the application of threonine aldolases. This review summarizes the recent advances in discovery, catalytic mechanism, high-throughput screening, molecular engineering and applications of threonine aldolases, with the aim to provide some insights for further research in this field.
Amino Acids ; Catalysis ; Glycine ; Glycine Hydroxymethyltransferase/metabolism* ; Kinetics ; Substrate Specificity ; Threonine

OBJECTIVE: To investigate function of glycine receptors (GlyRs) at the hippocampal CA1 pyramidal cells and to characterize the pharmacological properties of these receptors at early postnatal stage. METHODS: We used whole cell patch clamp recording to study the current response in the acutely prepared hippocampal slices from postnatal day 11-13 rats induced by glycine applied in the artificial cerebrospinal fluid. RESULTS: Application of glycine to the pyramidal cells elicited strychnine sensitive chloride currents. EC50 for GlyRs respond to glycine was 123. 23 μmol/L and Hill coefficient was 1.24. Picrotoxin could partly blocked the currents. CONCLUSION Strychnine sensitive glycine receptors are functionally expressed in CA1 pyramidal neurons in rat hippocampal CA1 area at early postnatal stage, and some of GlyRs are αβ heteromeric receptors.
Animals ; CA1 Region, Hippocampal ; cytology ; Glycine ; pharmacology ; Patch-Clamp Techniques ; Pyramidal Cells ; drug effects ; Rats ; Receptors, Glycine ; metabolism ; Strychnine ; pharmacology

AIMTo study changes of function of transmitter glycine in nitrogen narcosis.

METHODSSynaptosomes of rat spinal cord were prepared. Glycine uptake of synaptosomes of rat spinal cord in 0.7 MPa (7ATA) hyperbaric air pressure was observed by the methods of isotope.

RESULTSGlycine uptake slowed down and took a longer period of time to reach saturation in 0.7 MPa (7ATA). The maximum glycine uptake was lessened. Vm was diminished, but Km was increased. Vm rose in 0.7 MPa (7ATA) when corticosterone was added.

CONCLUSIONWhen nitrogen narcosis arose in 0.7 MPa (7ATA), the function of transporters of glycine re-uptake was reduced, the affinity of glycine for transporters subsided. Corticosterone was conductive to the recovery of the function of glycine transporters of high affinity.

Air Pressure ; Animals ; Glycine ; metabolism ; Rats ; Rats, Sprague-Dawley ; Spinal Cord ; metabolism ; Synaptosomes ; metabolism

Radioactive C(14)-glycine was given to Clonorchis sinensis in Tyrode medium in order to trace the metabolic fate of the labeled carbon. The labeled carbon from glycine enters into every major fraction of Clonorchis sinensis and is highest in the fraction of protein and nucleic acid. Significant amount of C(14)-glycine is incorporated into respiratory carbon dioxide. Relatively high percentage of C(14)-glycine in medium is converted to amino acid fraction and lipid fraction of the worm. In general, glycine is continuously being utilized in the synthesis of proteins and for energy production despite the uptake rate of glycine decreased gradually as incubation proceeds.
parasitology-helminth-trematoda ; Clonorchis sinensis ; metabolism ; biochemistry ; glycine ; amino acid ; nucleic acid ; protein ; lipid ; Tyrode medium

PURPOSE: Ultraviolet (UV) irradiation decreases epidermal hydration, which is maintained by reduction of natural moisturizing factors (NMFs). Among various NMFs, free amino acids (AA) are major constituents generated by filaggrin degradation. This experiment was conducted to determine whether or not dietary supplementation of green tea extract (GTE) in UV-irradiated mice can improve epidermal levels of hydration, filaggrin, free AAs, and peptidylarginine deiminase-3 (PAD3) expression (an enzyme involved in filaggrin degradation). METHODS: Hairless mice were fed a diet of 1% GTE for 10 weeks in parallel with UV irradiation (group UV+1%GTE). As controls, hairless mice were fed a control diet in parallel with (group UV+) or without (group UV-) UV irradiation. RESULTS: In group UV+, epidermal levels of hydration and filaggrin were lower than those in group UV-; these levels increased in group UV+1% GTE to levels similar to group UV-. Epidermal levels of PAD3 and major AAs of NMF, alanine, glycine and serine were similar in groups UV- and UV+, whereas these levels highly increased in group UV+1% GTE. CONCLUSION: Dietary GTE improves epidermal hydration by filaggrin generation and degradation into AAs.
Alanine ; Amino Acids ; Animals ; Diet ; Dietary Supplements ; Epidermis* ; Glycine ; Metabolism* ; Mice ; Mice, Hairless* ; Serine ; Tea*

Amino Acid Metabolism, Inborn Errors ; genetics ; Female ; Glycine N-Methyltransferase ; deficiency ; genetics ; Humans ; Infant, Newborn ; Mutation

A stable Zr-based metal-organic framework (MOF, UiO-66-NH2) synthesized via micro-water solvothermal method was used to immobilize amidase by using the glutaraldehyde crosslinking method. The effect of immoblization conditions on enzyme immoblization efficiency was studied. An activity recovery rate of 86.4% and an enzyme loading of 115.3 mg/g were achieved under the optimal conditions: glutaraldehyde concentration of 1.0%, cross-linking time of 180 min, and the weight ratio of MOF to enzyme of 8:1. The optimal temperature and optimal pH of the immobilized amidase were determined to be 40 °C and 9.0, respectively, and the Km, Vmax and kcat of the immoblized amidase were 58.32 mmol/L, 16.23 μmol/(min·mg), and 1 670 s⁻¹, respectively. The immobilized enzyme was used for (S)-4-fluorophenylglycine synthesis and the optimal reaction conditions were 300 mmol/L of N-phenylacetyl-4-fluorophenylglycine, 10 g/L of immobilized enzyme loading, and reacting for 180 min at pH 9.0 and 40 °C. A conversion rate of 49.9% was achieved under the optimal conditions, and the conversion rate can be increased to 99.9% under the conditions of enantiomeric excess. The immobilized enzyme can be repeatedly used, 95.8% of its original activity can be retained after 20 cycles.
Amidohydrolases ; Enzyme Stability ; Enzymes, Immobilized/metabolism* ; Glycine/analogs & derivatives* ; Hydrogen-Ion Concentration ; Metal-Organic Frameworks ; Temperature

Animals ; Fatty Liver ; metabolism ; pathology ; Glycine ; pharmacology ; Liver ; metabolism ; pathology ; Male ; PPAR gamma ; metabolism ; Rats ; Rats, Wistar

The impacts of osmoprotectants and nutrient components on both ethanol tolerance of Saccharomyces cerevisiae X330 and its ethanol fermentability were investigated when high gravity synthetic medium were used. The results indicate that nutrient limitation plays important role in the ethanol tolerance of Saccharomyces cerevisiae. When the nutritional requirements of Saccharomyces cerevisiae are satisfied, its ethanol tolerance increases, especially at high sugar concentrations. The effect of the individual nutrient component in the PYN medium on ethanol tolerance is different, which is yeast extract > peptone > magnesium sulfate > vitamin C = potassium phosphate > calcium chloride = ammonium sulfate. Osmoprotectants ( such as glycine and proline ) are effective in improving the ethanol tolerance of Saccharomyces cerevisiae X330, and the optimum concentrations of 20 mmol/L glycine and 10 mmol/L proline were obtained experimentally while glycine exerted a stronger enhancing effect than proline. After 3 h of exposure to 18% (V/V) ethanol at 30 degrees C, 57.1% and 50.0% remained viable for the cells grown in glycine-added and proline-added medium respectively.
Bioreactors ; microbiology ; Culture Media ; Drug Tolerance ; Ethanol ; metabolism ; pharmacology ; Fermentation ; Glycine ; metabolism ; Proline ; metabolism ; Saccharomyces cerevisiae ; drug effects ; growth & development

OBJECTIVETo investigate the protective effects of glycyl-glutamine dipeptide supplement on the function of myocardial dynamics in severely burned rats, and to explore its mechanism.

METHODSOne hundred and thirty-six Wistar rats were randomly divided into five groups: i. e, control group (C, n = 8, without burns), burn group (B, n = 32), Gln group (Gln, n = 32), Gly group (Gly, n = 32) and Gly-Gln group (Gly-Gln, n = 32). The rats in the latter four groups were respectively treated with tyrosine (1.5 g x kg(-1) x d(-1)), glutamine (1.0 g x kg(-1) x d(-1)) and tyrosine (0.5 g x kg(-1) x d(-1)), glycine (0.5 g x kg(-1) x d(-1)) and tyrosine (1.0 g x kg(-1) x d(-1)), and Glycyl-glutamine dipeptide (1.5 g x kg(-1) x d(-1)) after receiving a 30% TBSA full-thickness burn on the back. Glutathione (GSH), adenosine monophosphate (AMP), adenosine diphosphate (ADP), adenosine triphosphate (ATP), cell energy charge (EC) and the index of myocardial dynamics (ASOP, AODP, LVSP, + dp/dtmax) were measured at 12, 24, 48, 72 post-burn hours (PBH).

RESULTSThe content of GSH, ATP, EC and the level of aortic systolic pressure (ASOP), aortic diastolic blood pressure (AODP), left ventricular end diastolic pressure (LVEDP) and maximum rate of intraventricular pressure rise/down (+ dp/dtmax) in B, Gln, Gly, Gly-Gln groups were obviously lower than those in C group (P < 0.01), while the levels of AMP and ADP showed an opposite tendency. Compared with B group, the above indices were ameliorated. The content of GSH (72.7 +/- 1.7) micromol/g in Gly-Gln group at 12 PBH was obviously higher than that in Gln group (67.8 +/- 3.8) micromol/g (P < 0.01). The levels of EC and AOSP were obviously higher in Gly-Gln group than that in Gln group (P < 0.01). The level of GSH, EC, AOSP in Gly-Gln groups were obviously higher than those in Gly group at 48 PBH.

CONCLUSIONGlycyl-glutamine dipeptide, Gly and Gln supplementation after burns can improve the content of GSH and high energy phosphate compound, and suppress the decline of myocardial dynamics function. The effects of Glycyl-glutamine dipeptide is better than single Gly or Gln, indicating that the protective effect on myocardial function after severe burns by Gln and Gly is synergistic.

Animals ; Burns ; drug therapy ; metabolism ; Dipeptides ; pharmacology ; Glutathione ; metabolism ; Glycine ; Myocytes, Cardiac ; drug effects ; metabolism ; Random Allocation ; Rats ; Rats, Wistar