Characterization of RNA polymerase type II from human term placenta

Area of Science:

• Molecular Biology
• Enzymology

Background:

• RNA polymerase type II is crucial for gene transcription in eukaryotes.
• Understanding its properties is key to deciphering gene regulation.

Purpose of the Study:

• To isolate and characterize RNA polymerase type II from human term placenta.
• To determine the enzyme's preferences and kinetic parameters.

Main Methods:

• Isolation and purification of RNA polymerase type II.
• Enzyme characterization including template, salt, cation, and buffer preferences.
• Determination of Michaelis constants for AMP and UMP incorporation.
• Analysis using native and denaturing polyacrylamide gel electrophoresis.
• Photolabeling with azido purine nucleoside triphosphate.

Main Results:

• RNA polymerase type II from human placenta was successfully isolated and characterized.
• Specific preferences for template, ammonium sulfate, divalent cations, and buffers were identified.
• Apparent Michaelis constants for adenosine monophosphate (AMP) and uridine monophosphate (UMP) incorporation were determined.
• Polyacrylamide gel electrophoresis revealed a single polypeptide component labeled by photoprobes.

Conclusions:

• The characterized human placental RNA polymerase type II exhibits specific biochemical properties.
• The enzyme appears to be a single polypeptide entity, as indicated by photolabeling studies.