PMC:6194691 / 107823-108812 JSONTXT

{"project":"MyTest","denotations":[{"id":"30340614-2882529-30706331","span":{"begin":921,"end":924},"obj":"2882529"},{"id":"30340614-9580550-30706332","span":{"begin":926,"end":929},"obj":"9580550"}],"namespaces":[{"prefix":"_base","uri":"https://www.uniprot.org/uniprot/testbase"},{"prefix":"UniProtKB","uri":"https://www.uniprot.org/uniprot/"},{"prefix":"uniprot","uri":"https://www.uniprot.org/uniprotkb/"}],"text":"The need for amino acid input is different from the need for glucose input. Glucose is the basic fuel consumed in metabolism and must be supplied continually in large quantities. Amino acids are needed to allow the maintenance of cell structure and composition. But, the N containing constituents of the cells either are not consumed during metabolism or if they are they are partly replaced internally. The balance between influx and efflux across the blood–brain barrier need only provide sufficient amounts of amino acids to top up losses. Any metabolic losses that do occur will either be by efflux from the brain or by generation of NH4+ and carbon compounds. The latter become part of the carbon metabolism of cells. Possible fates of the NH4+ include: diffusion across the blood–brain barrier; reaction with glutamate to form glutamine, which is then exported from the parenchyma; and use in amino acid synthesis [359, 360]. Glutamate synthesis is considered further in Sect. 5.5.5."}

{"project":"2_test","denotations":[{"id":"30340614-2882529-30706331","span":{"begin":921,"end":924},"obj":"2882529"},{"id":"30340614-9580550-30706332","span":{"begin":926,"end":929},"obj":"9580550"}],"text":"The need for amino acid input is different from the need for glucose input. Glucose is the basic fuel consumed in metabolism and must be supplied continually in large quantities. Amino acids are needed to allow the maintenance of cell structure and composition. But, the N containing constituents of the cells either are not consumed during metabolism or if they are they are partly replaced internally. The balance between influx and efflux across the blood–brain barrier need only provide sufficient amounts of amino acids to top up losses. Any metabolic losses that do occur will either be by efflux from the brain or by generation of NH4+ and carbon compounds. The latter become part of the carbon metabolism of cells. Possible fates of the NH4+ include: diffusion across the blood–brain barrier; reaction with glutamate to form glutamine, which is then exported from the parenchyma; and use in amino acid synthesis [359, 360]. Glutamate synthesis is considered further in Sect. 5.5.5."}