Browsing by Author "MEDINA, A"

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    DEOXYRIBONUCLEIC-ACID POLYMERASE FROM THE MARINE PSEUDOMONAS SP BAL-31
    (1980) VICUNA, R; VALDES, F; MEDINA, A; YUDELEVICH, A
    A DNA-dependent DNA polymerase (DNA nucleotidyltransferase) was purified 3000-fold from the marine Pseudomonas sp. BAL-31. The MW of the native enzyme was estimated by glycerol gradient sedimentation to be 110,000. The enzyme migrated in sodium dodecyl sulfate-acrylamide gels as a single polypeptide with a MW of 105,000. An absolute requirement for divalent cation was satisfied by Mg2+ or Mn2+ at concentrations of 1 mM. Monovalent cations at concentrations higher than 50 mM showed an inhibitory effect. The polymerase activity was resistant to N-ethylmaleimide and showed a wide pH optimum.
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    STRUCTURE OF THE EUKARYOTIC GENOME - A UNIQUE PSEUDOGENE LACKING INTRONS AND POLY-A TAIL AS A MEMBER OF THE HUMAN BETA-TUBULIN GENE FAMILY
    (1982) PICHUANTES, S; MEDINA, A; BELL, G; GOMEZ, I; VALENZUELA, P; BULL, P; VENEGAS, A
    From a human gene bank constructed in the vector phage Charon 4A, 14 clones carrying complementary sequences to .alpha. and .beta. tubulin chicken c[complementary]DNA were isolated. A preliminary structural analysis of some of the .beta. clones, based on restriction digests followed by Southern hybridization, allowed us to select clone .beta.9 as the one containing a functional gene. After further analysis this clone was proved to contain a pseudogene. The coding sequence is altered by 4 stop codons, 6 short delections and 2 1-base insertions. These changes prevent any correct translation. The pseudogene seems to preserve some vestigial control regions and does not contain introns. No in vitro RNA synthesis directed by this clone was detected.