Abstract: The embodiments herein provide methods to analyze the in vitro stability of recalcitrant or membrane-bound proteins in simulated gastric fluid (SGF) comprising the proteolytic enzyme, pepsin, and in combination with a novel pepsin-trypsin assay employing state-of-the-art mass spectrometric approaches, such as LC-MS/MS, to monitor the precise degradation products. The extent of protein digestion can be evaluated by the appearance of peptic products and the disappearance of tryptic peptide products (as a proxy for intact protein). The embodiments herein also provide methods for protein quantitation using high-sensitivity LC-MRM-MS quantification. The methods embodied herein are particularly useful in charactering proteins produced in transgenic plants, such as canola genetically engineered to produce long chain omega-3 polyunsaturated fatty acids.

Abstract: The embodiments herein provide methods to analyze the in vitro stability of recalcitrant or membrane-bound proteins in simulated gastric fluid (SGF) comprising the proteolytic enzyme, pepsin, and in combination with a novel pepsin-trypsin assay employing state-of-the-art mass spectrometric approaches, such as LC-MS/MS, to monitor the precise degradation products. The extent of protein digestion can be evaluated by the appearance of peptic products and the disappearance of tryptic peptide products (as a proxy for intact protein). The embodiments herein also provide methods for protein quantitation using high-sensitivity LC-MRM-MS quantification. The methods embodied herein are particularly useful in charactering proteins produced in transgenic plants, such as canola genetically engineered to produce long chain omega-3 polyunsaturated fatty acids.

Abstract: The invention herein is directed to a process for the preparation of ethyl 3S-amino-4-pentynoate which involves treating 3-(trimethylsilyl)-2-propynal with L-phenylglycinol in toluene to produce .alpha.S-??3-(trimethylsilyl)-2-propynylidene amino!benzenethanol; reacting .alpha.S-??3-(trimethylsilyl)-2-propynylidene!amino!benzenethanol with BrZnCH.sub.2 CO.sub.2 t-Bu in THF/NMP to produce 1,1-dimethylethyl 3S-?(2-hydroxy-1S-phenylethyl)amino!-5-(trimethylsilyl)-4-pentynoate; reacting the 1,1-dimethylethyl 3S-?(2-hydroxy-1S-phenylethyl)amino!-5-(trimethylsilyl)-4-pentynoate with sodium periodate to form 1,1-dimethylethyl 3S-?(phenylmethylene)amino!-5-(trimethylsilyl)-4-pentynoate; hydrolyzing 1,1-dimethylethyl 3S-?(phenylmethylene)amino!-5-(trimethylsilyl)-4-pentynoate to produce 1,1-dimethylethyl 3S-amino-5-(trimethylsilyl)-4-pentynoate; transesterifying 1,1-dimethyl 3S-amino-5-(trimethylsilyl)-4-pentynoate and desilylating to produce ethyl 3S-amino-4-pentynoate.