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L L Henderson

Publications and source records attributed to L L Henderson.

At least 19 recordsLinked to original sources
PubMed1984

Purification and characterization of epimeric estradiol dehydrogenases (17 alpha and 17 beta) from equine placenta.

Estradiol 17 alpha-dehydrogenase (EC 1.1.1.148) and estradiol 17 beta-dehydrogenase (EC 1.1.1.62) from horse placenta have been purified to homogeneity. Both enzymes are localized in the microsomal fraction and are solubilized in 1.5% sodium cholate. The 17 alpha- and 17 beta-dehydrogenases are separated by selective elution from hydroxylapatite with 0.5 and 1.0 M potassium phosphate, respectively. Subsequent purification is achieved by two affinity-absorption steps using reactive blue 2-agarose and estriol hemisuccinate-Sepharose. Homogeneous estradiol 17 alpha-dehydrogenase has a specific activity of 10 IU/mg and has been purified 5900-fold with an 87% recovery. Homogeneous estradiol 17 beta-dehydrogenase has a specific activity of 10.6 IU/mg and has been purified 15 000-fold with an apparent recovery of 100%. Each enzyme exhibits a single band on polyacrylamide disc gel electrophoresis and on sodium dodecyl sulfate (SDS) gel electrophoresis. The mobilities of the two on SDS gels are identical and correspond to subunit molecular weights of 33000. The apparent molecular weight of the undenatured, active enzyme, as determined by gel filtration on Sephacryl S-300, is 52000 in the case of the 17 alpha-dehydrogenase and 68500 for the 17 beta-dehydrogenase. Both enzymes exhibit pH optima at 9.0-9.5; both prefer NAD+ over NADP+ but utilize both cofactors. Both are highly specific for their respective epimers of estradiol with apparent Km values of 1.7 microM at pH 9.5.

17-Hydroxysteroid Dehydrogenases↗
PubMed1981

Effect of ascorbic acid deficiency on the in vivo synthesis of carnitine.

The effects of ascorbate deficiency on carnitine biosynthesis was investigated in young male guinea pigs. Liver and kidney carnitine levels were not affected by the deficiency, but scorbutic animals had 50% less carnitine in heart and skeletal muscle than control animals. Labeled carnitine precursors, 6-N-tri-methyl-L-lysine and 4-N-trimethylaminobutyrate, both of which require ascorbate for their enzymatic hydroxylation, were injected into the vena cava of control, pair-fed and scorbutic animals. The distribution of isotope in compounds present in the liver and kidney after 1 h was determined. The uptake of trimethyllysine by the liver was less than 2% in 1 h, while the kidney took up approx. 20% of the 14C. Control and pair-fed animals converted trimethyllysine to kidney trimethylaminobutyrate 8--10 times as well as did scorbutic animals. Trimethylaminobutyrate hydroxylase, present in the liver but almost absent from the kidney, converted nearly all of substrate taken up by the liver to carnitine in both the scorbutic and control animals.

Animals↗
PubMed1975

Maximal rise in IgE antibody following ragweed pollination season.

Patients allergic to ragweed pollen who did not receive immunotherapy had an increase in ragweed-specific IgE antibodies associated with seasonal exposure. Of 17 such patients, 15 reached peak levels between mid-September and mid-October. Two had peak values after mid-October; the levels were only slightly higher than earlier values. Our study shows that serum obtained in mid-October reflects approximately the maximal IgE antibody level attained 0y ragweed-sensitive patients in our area and that this value can be used as a baseline in monitoring the subsequent decline in antibodies. In addition, our data support an earlier observation that the magnitude of seasonal rise in IgE antibody is related to the preseasonal value. The significantly positive correlation of the results of carefully performed skin tests (end point titration) with radioallergosorbent test (RAST) values suggests the possibility that the RAST can be employed as a reliable diagnostic aid, perhaps even replacing the skin test.

Adolescent↗
PubMed1967

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Humans↗