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H L Katcher

Publications and source records attributed to H L Katcher.

5 recordsLinked to original sources
PubMed1994

A distinctive property of Tth DNA polymerase: enzymatic amplification in the presence of phenol.

The ability of thermostable DNA polymerases to mediate template-dependent DNA synthesis in the presence of phenol has been examined as monitored by amplification of a specific Borrelia burgdorferi rRNA sequence. Tth DNA polymerase displayed the unique property of maintaining both DNA- and RNA-dependent DNA polymerase activities in the presence of 2%-5% (vol/vol) of phenol-saturated PBS buffer. Tth DNA polymerase mediated reverse transcriptase activity was unaffected by phenol-saturated phosphate-buffered saline concentrations as high as 15% (vol/vol). By contrast, Taq DNA Polymerase was inactive under these conditions. The ability to function in the presence of phenol can greatly simplify reverse transcriptase, PCR and reverse transcription-PCR protocols since the phenol-saturated aqueous phase of a phenol partition can be added directly to the reaction mixtures. The simplicity of the procedures described should have applicability to a broad range of basic research, clinical and forensic applications.

Borrelia burgdorferi Group↗
PubMed1992

A simple and rapid method to study the association of the contact proteins of blood coagulation.

Native and reduced SDS polyacrylamide gel electrophoresis on the automated PhastSystem (Pharmacia) were used to demonstrate protein-protein binding interactions and structural changes during proteolytic activations of the proteins involved in contact activation. The "mobility shift" assay in native gels has been used to visualize the kinetics of activation of factor XII by dextran sulfate as well as the formation of kallikrein-cleaved high molecular weight kininogen. It shows the formation of prekallikrein-high molecular weight kininogen complexes and factor XII-dextran sulfate complex for the first time in gels. The use of automation makes this procedure fast and reproducible using nanogram amounts of protein in relatively short time.

Amino Acid Sequence↗
PubMed1984

Algorithms for restriction map comparisons.

An algorithm is presented which compares two restriction maps, yielding a measure of distance between the maps and relating the maps by an alignment. This new algorithm finds the minimum weighted sum of genetic events required to convert one map into the other, where the genetic events are the appearance/disappearance of restriction sites and changes in the number of bases between restriction sites. The algorithm is illustrated by comparison of the beta-delta region of the globin gene cluster of four primate species. The results are in excellent agreement with known evolutionary relationships.

Animals↗
PubMed1983

Characterization of the Escherichia coli X-ray endonuclease, endonuclease III.

The X-ray endonuclease endonuclease III of Escherichia coli has been purified to apparent homogeneity by using the criterion of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The most purified fraction shows endonucleolytic activity against apurinic and apyrimidinic (AP) sites and a dose-dependent response to DNA that has been X irradiated, UV irradiated, or treated with OsO4. The endonuclease also nicks OsO4-treated DNA that has been subsequently treated with alkali to produce fragmented thymine residues and DNA treated with potassium permanganate. The enzyme does not incise the alkali-labile sites present in DNA X irradiated in vitro in the presence of hydroxyl radical scavengers. The most purified fractions exhibit two distinct activities, an AP endonuclease that cleaves on the 3' side of the damage leaving a 3'-OH and a 5'-PO4 and a DNA N-glycosylase that recognizes at least two substrates, thymine glycol residues and urea residues. The glycosylase activity is sensitive to N-ethylmaleimide while the AP endonuclease is not.

DNA Polymerase I↗