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Biomedical subjects

C E French

Publications and source records attributed to C E French.

25 records · Page 2Linked to original sources
PubMed1995

Biological production of semisynthetic opiates using genetically engineered bacteria.

Semisynthetic derivatives of morphine and related alkaloids are in widespread clinical use. Due to the complexity of these molecules, however, chemical transformations are difficult to achieve in high yields. We recently identified the powerful analgesic hydromorphone as an intermediate in the metabolism of morphine by Pseudomonas putida M10. Here we describe the construction of recombinant strains of Escherichia coli that express morphine dehydrogenase and morphinone reductase. These strains are capable of efficiently transforming the naturally occurring alkaloids morphine and codeine to hydromorphone and the antitussive hydrocodone, respectively. Our results demonstrate the potential for recombinant DNA technology to provide biological routes for the synthesis of known and novel semisynthetic opiate drugs.

Alcohol Oxidoreductases↗
PubMed1994

Purification and characterization of morphinone reductase from Pseudomonas putida M10.

The NADH-dependent morphinone reductase from Pseudomonas putida M10 catalyses the reduction of morphinone and codeinone to hydromorphone and hydrocodone respectively. Morphinone reductase was purified from crude cell extracts to apparent homogeneity in a single affinity-chromatography step using Mimetic Yellow 2. The purified enzyme was a dimeric flavoprotein with two identical subunits of M(r) 41,100, binding non-covalently one molecule of FMN per subunit. The N-terminal sequence was PDTSFSNPGLFTPLQ. Morphinone reductase was active against morphinone, codeinone, neopinone and 2-cyclohexen-1-one, but not against morphine, codeine or isocodeine. The apparent Km values for codeinone and 2-cyclohexen-1-one were 0.26 mM and 5.5 mM respectively. The steroids progesterone and cortisone were potent competitive inhibitors; the apparent K1 for cortisone was 35 microM. The pH optimum for codeinone reduction was 8.0 in phosphate buffer. No reverse reaction could be detected, and NADPH could not be used as a reducing substrate in place of NADH. Morphinone reductase activity was strongly inhibited by 0.01 mM CuSO4 and p-hydroxymercuribenzoate, suggesting the presence of a vital thiol group. Steady-state kinetic studies suggested a Ping Pong (substituted enzyme) kinetic mechanism; however, product-inhibition patterns were inconsistent with a classical Ping Pong mechanism. Morphinone reductase may, like several other flavoprotein dehydrogenases, operate by a hybrid two-site Ping Pong mechanism.

Amino Acid Sequence↗
PubMed1982

Subcapsular hemorrhage of the liver in the newborn.

Infants with large subcapsular hemorrhages of the liver may have signs that mimic hypovolemic shock commonly seen with intraventricular hemorrhage. A retrospective clinicopathologic study of 783 neonates spanning ten years disclosed an incidence of 15% for subcapsular hemorrhage of the liver. Infants at risk were not clearly distinguishable clinically from control cohorts, but tended to be premature male infants with chronic problems during gestation and more complications during labor and delivery. Physical manipulations including umbilical venous catheter placement, tracheal intubation, and chest tube placement were typically seen in the affected neonates.

Adult↗