Melanie E Jones

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The oxidation of proline to glutamate in mitochondria requires two enzymes, proline oxidase and pyrroline 5-carboxylate (P5C) dehydrogenase. In this paper we report an 800-fold purification P5C dehydrogenase from rat liver mitochondria to yield an essentially homogenous protein. The protein, whose Mr is 59,000, is an alpha 2 dimer (Mr = 115,000) in solution(More)
In vitro incubations (6 hr at 37 degrees C) of human low density lipoproteins (LDL), high density lipoproteins (HDL), and lipoprotein-free plasma revealed no significant net mass transfers of esterified cholesterol from either lipoprotein fraction to the other. Transfers of esterified [3H]cholesterol from LDL to HDL must therefore have represented a process(More)
Exchanges of esterified cholesterol between human high density lipoproteins (HDL) and very low density lipoproteins (VLDL) and between VLDL and low density lipoproteins (LDL) have been fitted to a mathematical model previously developed to describe exchanges between human HDL and LDL. In all cases the fit of the model predicted exchanges to those measured(More)
Previous studies of pyrroline-5-carboxylate dehydrogenase have been conducted using a spectrophotometric method to monitor substrate-dependent NAD(P)H production. For the assay of the mammalian enzyme, the spectrophotometric assay was found to be unacceptable for kinetic studies as the production of NAD(P)H was nonlinear with time and protein concentration.(More)
We have studied factors affecting the catalytic activity of dihydroorotase (EC 3.5.2.3), purified as part of a multienzymatic protein which contains carbamyl phosphate synthetase, aspartate transcarbamylase, and dihydroorotase (ME pyr1-3) and which initiates de novo pyrimidine biosynthesis in mouse Ehrlich ascites carcinoma. The apparent Km value for(More)