PMC:6194691 / 256060-256998 JSONTXT

{"target":"https://pubannotation.org/docs/sourcedb/PMC/sourceid/6194691","sourcedb":"PMC","sourceid":"6194691","source_url":"https://www.ncbi.nlm.nih.gov/pmc/6194691","text":"The results were later extended to allow calculation of Michaelis–Menten constants for each of the amino acids [372]. For the large neutral amino acids the Vmax and Km values varied from 30 nmol g−1 min−1 and 0.12 mM for phenylalanine to 49 nmol g−1 min−1 and 0.63 mM for valine. Competition reduces the fluxes seen for each amino acid but for any one transporter may have a Vmax for the combination of amino acids present somewhere in the range observed for the individual amino acids. Thus from these results from the rat studies the maximum collective influx of the large neutral amino acids is expected to be less than 50 nmol g−1 min−1. Smith and Stoll [43] provide a useful table of influxes from nearly normal composition of plasma with a total influx of 72 nmol g−1 min−1. It should be noted that (a) this total is for the influx not the net flux and (b) virtually all of the data for tracer influxes have been obtained with rats.","tracks":[]}