Biomedical subjects

W H Voige

Publications and source records attributed to W H Voige.

3 recordsLinked to original sources

PubMed1988

Cloning and expression in Escherichia coli of the Alcaligenes eutrophus H16 poly-beta-hydroxybutyrate biosynthetic pathway.

The poly-beta-hydroxybutyrate (PHB) biosynthetic pathway from Alcaligenes eutrophus H16 has been cloned and expressed in Escherichia coli. Initially, an A. eutrophus H16 genomic library was constructed by using cosmid pVK102, and cosmid clones that encoded the PHB biosynthetic pathway were sought by assaying for the first enzyme of the pathway, beta-ketothiolase. Six enzyme-positive clones were identified. Three of these clones manifested acetoacetyl coenzyme A reductase activity, the second enzyme of the biosynthetic pathway, and accumulated PHB. PHB was produced in the cosmid clones at approximately 50% of the level found in A. eutrophus. One cosmid clone was subjected to subcloning experiments, and the PHB biosynthetic pathway was isolated on a 5.2-kilobase KpnI-EcoRI fragment. This fragment, when cloned into small multicopy vectors, can direct the synthesis of PHB in E. coli to levels approaching 80% of the bacterial cell dry weight.

Acetyl-CoA C-Acyltransferase↗

PubMed1984

Purification and characterization of succinyl-CoA: tetrahydrodipicolinate N-succinyltransferase from Escherichia coli.

Tetrahydrodipicolinate succinylase, an enzyme involved in the diaminopimelate-lysine pathway, was purified 1900-fold from crude extracts of Escherichia coli. The enzyme catalyzes the formation of CoA and N-succinyl-2-amino-6-keto-L-pimelate from succinyl-CoA and tetrahydrodipicolinate. The purified enzyme was shown to be homogeneous by polyacrylamide gel electrophoresis. The Stokes radius of the enzyme was determined from its elution volume on a Sephacryl S300 column and its sedimentation constant from sucrose density gradient centrifugation. These were 35 A and 4.7 (S20,w), respectively. The enzyme consists of two subunits each with a mass of 31,000 daltons, as determined using sodium dodecyl sulfate/polyacrylamide gel electrophoresis. Tetrahydrodipicolinate succinylase was shown to be a sulfhydryl enzyme. It has a pH optimum of 8.2. The equilibrium lies predominantly in favor of product formation but the reverse reaction can be demonstrated in vitro.

Acyltransferases↗

PubMed1983

Improved methods for calculating formation constants for nucleotide--cation complexes.

Two data reduction methods that can be used to calculate formation constants for nucleotide-cation complexes are described. Both methods are used to analyze data obtained by an anion-exchange resin method, and either method can improve the accuracy of the calculated formation constants by more than 50%. The key to this significant improvement in accuracy is the realization that the equation for the mathematical model describing such systems is always nonlinear in terms of the formation constants and, in the general case, is higher order in the cation concentration. There are two major reasons for the improved quality of the results associated with the new model. First, successive linear extrapolations are eliminated, and error propagation is reduced. Second, all of the data are used for the simultaneous calculation of all formation constants, and the uncertainty due to random experimental errors is minimized.

Anion Exchange Resins↗