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Creatine is a popular athletic supplement that has also been shown to improve cognitive performance upon sleep deprivation. However, it is rapidly cleared from the gastrointestinal tract a few hours after consumption. Toward providing a persistent creatine dose, we engineered the human probiotic Escherichia coli Nissle (EcN) to produce guanidinoacetic acid (GAA), which is converted […]

To establish an indirect competitive ELISA (ci-ELISA) for the detection of guanidino acetic acid (GAA) residues in animal feed, in this study, GAA was coupled to carrier proteins via the active ester method to obtain an anti-GAA complete antigen (GAA-BSA) and a detection antigen (GAA-OVA). BALB/c mice were immunized with GAA-BSA, after which anti-GAA monoclonal […]

Guanidinoacetic acid, as an energetic substance, has a wide range of applications in the food, pharmaceutical, and feed industries. However, the biosynthesis of guanidinoacetic acid has not been applied in industrial production. In this study, we designed the synthetic route of guanidinoacetic acid in a food-grade strain of Bacillus subtilis. By regulating the expression of […]

Creatine is a naturally occurring derivative of an amino acid commonly utilized in functional foods and pharmaceuticals. Nevertheless, the current industrial synthesis of creatine relies on chemical processes, which may hinder its utilization in certain applications. Therefore, a biological approach was devised that employs whole-cell biocatalysis in the bacterium Corynebacterium glutamicum, which is considered safe […]

Here the authors report the engineering of human red blood cells with an entire metabolic pathway as a potential strategy to treat patients with guanidinoacetate methyltransferase (GAMT) deficiency, capable of reducing the high toxic levels of guanidinoacetate acid (GAA) and restoring proper creatine levels in blood and tissues. We first produced a recombinant form of […]

Guanidinoacetic acid (GAA) is a naturally occurring precursor to creatine, an source of energy for skeletal muscle. Feeding GAA to chickens, pigs and cattle improves growth performance through a mechanism that may include increased serum IGF-1 and feed conversion. The formation of creatine from GAA uses a considerable number of methyl donors, arginine and glycine […]

The accurate and efficient measurement of small molecule disease markers for clinical diagnosis is of great importance. In this study, a quadrupole-linear ion trap (Q-LIT) tandem mass spectrometer was designed and built in our laboratory. Target precursor ions were first selected in the quadrupole, and then injected, trapped, and fragmented simultaneously in the linear ion […]

Guanidinoacetate methyltransferase deficiency is an inborn error of metabolism that results in decreased creatine and increased guanidinoacetate (GAA) levels. Patients present neurological symptoms whose mechanisms are unclear. We investigated the effects of an intrastriatal administration of 10 μM of GAA (0.02 nmol/striatum) on energy metabolism, redox state, inflammation, glutamate homeostasis, and activities/immunocontents of acetylcholinesterase and […]

Quantitative amino acid analysis has diverse applications in clinical diagnostics, biomedical research, and agriculture. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) enables more rapid and specific detection of amino acids in comparison to traditional, gold-standard ninhydrin-based methods. However, triple quadrupole mass spectrometers are unable to definitively differentiate isomers and are susceptible to ion suppression, both of which […]

A simple, rapid and sensitive HPLC-MS/MS method for simultaneous determination of 4 of amino acids, guanidinoacetic acid, S-adenosylmethionine and S-adenosylhomocysteine in human plasma was developed and validated. The method requires no tedious sample preparation, derivatization reagents or ion-pairing reagents. Samples were prepared by combining plasma with a chilled mixture of acetonitrile (ACN) and water, followed […]