@article{oai:repo.qst.go.jp:00044304,
 author = {Sasaki, Motoji and Ikemoto, Masahiro and Mutou, Masatoshi and Haradahira, Terushi and Tanaka, Akira and Watanabe, Yoshito and Suzuki, Kazutoshi and 佐々木 基仁 and 池本 昌弘 and 原田平 輝志 and 渡辺 嘉人 and 鈴木 和年},
 journal = {Applied Radiation and Isotopes},
 month = {},
 note = {We have developed a system for the automatic synthesis of L-[beta-11C]amino acids for i.v.injection by means of enzyme-mediated reactions from 11CO2 via 11CH3I and D,L-[beta-11C]alanine as labeled intermediates. This system, which incorporates an ultrafilter cartridge sterilized by electron beam irradiation and a column packed with immobilized enzymes, was effective for eliminating enzymes and endotoxins that may contaminate the product.  Using this system, 1.3+/-0.5GBq of 5-hydroxy-L-[beta-11C]tryptophan with a radiochemical purity of 97.1+/-0.6% and a specific activity of 39.6+/-8 GBq/mumol a pH value of 4 could be obtained in about 32 min(n=3,at EOS).  No endotoxin, enzyme, or bacteria was detected in the product.  L-[beta-11C} dihydroxyphenylalanine (L-[beta-11C]DOPA) was also synthesized using this system.},
 pages = {199--204},
 title = {Automatic synthesis of L-[beta-11C]amino acids using an immobilized enzyme column},
 volume = {52},
 year = {2000}
}