TABLE 1

Tissue processing and protease inhibitor combinations used in intestinal microsome preparations

Protocol	Tissue Processing	Protease Inhibitor Additions
Protocol	Tissue Processing			Tissue Homogenization Buffer	Microsome Resuspension Buffer
A	Scraping	None	1 mM EDTA
B	Scraping	0.1 mM PMSF	1 mM EDTA
		5 mg trypsin inhibitor/g wet weight	0.1 mM PMSF
C	Mincing	0.1 mM PMSF	1 mM EDTA
		5 mg trypsin inhibitor/g wet weight	0.1 mM PMSF
D	Scraping	1 mM EDTA	1 mM EDTA
		0.25 mM PMSF	0.1 mM PMSF
		0.1 mM dithiothreitol	5 μg/ml leupeptin
E	Scraping	1 mM EDTA	1 mM EDTA
		0.1 mM PMSF	0.1 mM PMSF
		1× protease inhibitor mixture^a	1× protease inhibitor mixture^a
F	Mincing	1 mM EDTA	1 mM EDTA
		0.1 mM PMSF	0.1 mM PMSF
		5 mg trypsin inhibitor/g wet weight	0.1 mg/ml trypsin inhibitor
		5× protease inhibitor mixture^b	5× protease inhibitor mixture^b

↵ a Contains the protease inhibitors (pepstatin A, chymostatin, antipain, leupeptin) at 0.1 μg/ml, and aprotinin at 0.04 μg/ml.
↵ b Contains the protease inhibitors (pepstatin A, chymostatin, antipain, leupeptin) at 0.5 μg/ml, and aprotinin at 0.2 μg/ml.