Improved estimation of DNA fragment lengths from Agarose gels |
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| Authors: | H E Schaffer R R Sederoff |
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| Institution: | 1. Department of Pharmacology, University of Texas Health Science Center, Dallas, Texas 75235 USA;2. Department of Internal Medicine, University of Texas Health Science Center, Dallas, Texas 75235 USA;3. Recombinant DNA Division, Southern Medical and Pharmaceutical Corporation, Tampa, Florida 33612 USA |
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| Abstract: | A simple, sensitive assay for prolylcarboxypeptidase (PCP) is described. It utilizes a radiolabeled substrate, benzyloxycarbonyl-l-prolyl-l-3H]alanine, and the details of its synthesis are also reported here. The hydrolysis of the dipeptide substrate is linear with respect to time or protein concentration until 10% of the substrate has been cleaved. Kinetic analysis yielded a Km of 4.7 mm. The assay can be used to measure PCP activity in small amounts of biological fluid, homogenized tissue or cultured cells. Measurements of PCP activity in various cultured human cells showed endothelial cells from umbilical veins to have the highest activity (1625 ± 151 nmol/mg/h) followed by endothelial cells from umbilical artery (1017 ± 46 nmol/mg/h), human foreskin fibroblasts (719 ± 39 nmol/mg/h), and pulmonary artery endothelial cells (352 nmol/mg/h). |
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| Keywords: | To whom correspondence should be addressed |
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