PCR and qPCR Optimization: Supplies Mg2+ cofactor for DNA polymerases, tuning annealing, yield, and specificity.

Reverse Transcription and In Vitro Transcription: Provides essential Mg2+ for RT and T7/T3/SP6 RNA polymerase activity.

Restriction Enzyme Digests: Delivers Mg2+ required for endonuclease activity and complete DNA cleavage.

Ligation Reactions: Supports T4 DNA ligase activity by supplying Mg2+ in ligation buffers.

Sanger Sequencing and DNA Polymerase Reactions: Ensures optimal polymerase function and read length.

Isothermal Amplification (LAMP, RPA): Adjusts Mg2+ concentration to drive robust isothermal DNA amplification.

Nuclease Assays (e.g., DNase I, RNase H): Provides Mg2+ cofactor for efficient nucleic acid cleavage.

Competent Cell Preparation and Transformation: Used in TSS/chemically competent protocols to enhance uptake in Escherichia coli.

Bacteriophage Plaque Assays: Supplements top agar with Mg2+ to improve phage adsorption and plating on Escherichia coli.

Protein–Nucleic Acid Binding Assays (EMSA): Stabilizes Mg2+-dependent DNA/RNA–protein interactions.

Protein Crystallization Additive: Used as a divalent salt to promote crystal formation and lattice stability.

Buffer and Physiological Saline Formulation: Included in HEPES/PBS-like solutions to set divalent cation strength for enzymes and ion channels.