蛋白质和肽中谷氨酰胺的HPLC定量分析

建立了肽及蛋白质中定量Ｇｌｎ 的ＨＰＬＣ 法。Ｇｌｎ 残基与双（１ ,１三氟乙酸基） 碘苯（ＢＴＩ） 反应后酸水解,生成的Ｌ２ ,４二氨基酸（ＤＡＢＡ） 用苯异硫氰酸酯（ＰＩＴＣ） 衍生化后,ＨＰＬＣ分析检测。用已知小肽和蛋白质（Ｇｌｙ ＝ Ｇｌｎ ,溶菌酶） 试验表明,回收率为９３－３ ％ ±５ ．０ ％ ～９６ ．０ ％ ±２ ．０ ％ ,精密度０－１５２８ ,标准偏差３－２２ ％ 。     

Determination of l- and d-amino acids in smokeless tobacco products and tobacco

Quantities of free l- and d-amino acids were determined by GC-SIM-MS in 25 European snuff tobaccos (from Germany, England and Sweden) and eight chewing tobaccos (from the Philippines, Africa and Denmark) and compared to those of cigar, cigarillo, and freshly harvested tobacco leaves of cultivars of Nicotiana tabacum L. Amino acids were isolated from tobacco samples by treatment with 70% aqueous methanol and purified by a cation exchanger. Next they were converted into their N(O)-pentafluoropropionylamino acid-(2)-propyl esters, and enantiomers separated and quantified by GC-SIM-MS on a Chirasil^®-l-Val capillary column. Among l-amino acids the most abundant were Pro, Asx and Glx in the low milligram range (about 2–6 mg/g) whereas the other l-amino acids were in the submilligram range. Though native tobacco leaves contained low amounts of few d-AAs (0.2–1.9%), all processed tobacco samples had d-amino acids in varying amounts and patterns.