1,720,979 research outputs found
A method for the assessment of the presence of an insert in lambda gt 11 clones during a cDNA library screening
No full textANAL BIOCHE
Bilitranslocase can exist in two metastable forms with different affinities for the substrates--evidence from cysteine and arginine modification
Full text linkBilitranslocase is an organic anion carrier involved in bilirubin and phthalein uptake by the liver. In rat liver plasma membranes, its function is assayed by recording the electrogenic sulfobromophthalein movement. This has been found to be inhibited by both cysteine-specific and arginine-specific reagents. Inhibition is both partial and it occurs to the same extent, i.e. approximately 50 %. The effects are not additive. Here we describe the mechanism underlying the above observations. It is concluded that bilitranslocase occurs in two possible states, featured by high and low affinity for the substrates (for sulfobromophthalein, Km = 5 μM and 37 μM, respectively). Cysteine- or arginine-reactive reagents, by reacting selectively with the low-affinity form, entrap it and shift the equilibrium between the two forms, so that, at completion, only the low-affinity form is present. The substrate concentration in the standard transport assay is 39 μM, a value at which the modified low-affinity form operates in the range of half-maximal velocity. This explains both the apparent half-inhibition measured after the chemical treatments and the lack of additivity. In addition, the substrates are shown to enhance the rate of conversion from the low-affinity to the high-affinity form of the translocator, thus favouring its high-affinity form under physiological conditions
Arylsulfonylation of bilitranslocase in plasma membranes from rat liver enables to discriminate between natural and artificial substrates
No full textBIOCHIM BIOPHYS ACT
On the mechanism of bilitranslocase transport inactivation by phenylmethylsulphonyl fluoride
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Reversal of ethanol-induced hepatic glutathione depletion by S-adenosyl-methionine in rats.
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