4,4-Difluoro-L-proline methyl

Quantitation of Cocaine, Benzoylecgonine, Ecgonine Methyl Ester, and Cocaethylene in Urine and Blood Using Gas Chromatography-Mass Spectrometry (GC-MS

, benzoylecgonine-d3, ecgonine methyl ester-d3, and cocaethylene-d3 and buffered with phosphate buffer. The drugs in the sample are extracted by cation-exchange solid phase extraction. The drugs from the solid phase cartridge are eluted and the eluent is dried

Incorporation of Phosphotyrosyl Mimetic 4- (Phosphonodifluoromethyl)phenylalanine (F2Pmp) Into Signal Transduction-Directed Peptides

useful properties of full phosphoproteins. However, such pTyr-containing peptides have limited use in whole-cell systems resulting from lability of the phosphate ester bond to protein-tyrosine phosphatases (PTPs). For this reason, a number of phosphatase

Enzymes Acting on d-Amino Acid Containing Peptides

aminopeptidase and endopeptidase activities. The enzyme was active toward (d -Phe) n , Boc-(d -Phe) n , (d -Phe) n methyl ester, d -Phe-NH2 , Boc-(d -Phe) n methyl ester, and Boc-(d -Phe) n tert -butyl ester, but not toward (d -Ala) n (n = 2–4), (d