Biochemical and Biophysical Research Communications, 1976
ABSTRACT Membrane vesicles of M. phlei actively take up proline in the absence of exogenously pro... more ABSTRACT Membrane vesicles of M. phlei actively take up proline in the absence of exogenously provided electron donors. Evidence is provided that endogenous transport is coupled to the oxidation-reduction of low-potential electron carriers, but does not involve the cytochromes. The endogenous transport was found to be enhanced under either aerobic or anaerobic conditions by the addition of certain artificial electron acceptors such as Cu2+.
ABSTRACT Filter-paper disks of uniform size were chemically modified by the introduction of isoni... more ABSTRACT Filter-paper disks of uniform size were chemically modified by the introduction of isonitrile functional groups. Avidin was then covalently linked to the disks in a four-component condensation reaction involving disk isonitrile groups and avidin carboxyl groups in the presence of a water-soluble aldehyde and an amine. Quantitative assay of unknown d-biotin solutions could be conveniently carried out with such avidin-cellulose disks by a two-step procedure: (i) immersion in the unknown sample, and (ii) exposure to an excess of radioactive biotin. Based on the known total capacity of the disks for biotin, the amount of unlabeled biotin extracted from solution by avidin-cellulose disks could be easily estimated.
ColE1 amp plasmids carrying the entire bio gene cluster were constructed in vitro using ColE1 amp... more ColE1 amp plasmids carrying the entire bio gene cluster were constructed in vitro using ColE1 amp as the cloning vehicle and a λ transducing phage, λatt 2,as the source of bio DNA. Restriction endonuclease EcoRI digests of ColE1amp and λatt 2DNA were joined by polynucleotide ligase and plasmids bearing the entire bio gene cluster were selected, after transformation, in bio deletion strains of E. coli. Recombinant DNA moleules contained one ColE1amp fragment (7.4×106 daltons) and one λatt 2DNA fragment (5.4×106 daltons). Clones carrying ColE1 amp-bio plasmids produce elevated levels of biotin and biotin synthetase activity.
Biochemical and Biophysical Research Communications, 1976
ABSTRACT Membrane vesicles of M. phlei actively take up proline in the absence of exogenously pro... more ABSTRACT Membrane vesicles of M. phlei actively take up proline in the absence of exogenously provided electron donors. Evidence is provided that endogenous transport is coupled to the oxidation-reduction of low-potential electron carriers, but does not involve the cytochromes. The endogenous transport was found to be enhanced under either aerobic or anaerobic conditions by the addition of certain artificial electron acceptors such as Cu2+.
ABSTRACT Filter-paper disks of uniform size were chemically modified by the introduction of isoni... more ABSTRACT Filter-paper disks of uniform size were chemically modified by the introduction of isonitrile functional groups. Avidin was then covalently linked to the disks in a four-component condensation reaction involving disk isonitrile groups and avidin carboxyl groups in the presence of a water-soluble aldehyde and an amine. Quantitative assay of unknown d-biotin solutions could be conveniently carried out with such avidin-cellulose disks by a two-step procedure: (i) immersion in the unknown sample, and (ii) exposure to an excess of radioactive biotin. Based on the known total capacity of the disks for biotin, the amount of unlabeled biotin extracted from solution by avidin-cellulose disks could be easily estimated.
ColE1 amp plasmids carrying the entire bio gene cluster were constructed in vitro using ColE1 amp... more ColE1 amp plasmids carrying the entire bio gene cluster were constructed in vitro using ColE1 amp as the cloning vehicle and a λ transducing phage, λatt 2,as the source of bio DNA. Restriction endonuclease EcoRI digests of ColE1amp and λatt 2DNA were joined by polynucleotide ligase and plasmids bearing the entire bio gene cluster were selected, after transformation, in bio deletion strains of E. coli. Recombinant DNA moleules contained one ColE1amp fragment (7.4×106 daltons) and one λatt 2DNA fragment (5.4×106 daltons). Clones carrying ColE1 amp-bio plasmids produce elevated levels of biotin and biotin synthetase activity.
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Papers by Saul Yankofsky