protein biochemistry
A glossary of protein-prep terms
Fourteen protein-prep words, from lysate to glycerol stock, each tied to the mistake it stops before a purification is misread.
8 October 2026 · 9 min read
Topic cluster
Protein biochemistry
Protein gels, quantification, buffers and purification choices explained for research laboratories.
All topicsBuffers and laboratory water26Cell culture26Chromatography26Cold chain and sample storage26Cytometry and microscopy26DNA sequencing26Gels and blotting26Gene expression26Genome editing26Immunoassays26Laboratory labware26Laboratory safety26Liquid handling26Microbiology26Molecular cloning26Nucleic acid purification26PCR and amplification26Protein biochemistry26Proteomics26Research sourcing and study design26
cold chainspecificationproteomicsenquiryglossarytroubleshootingbuffersquantificationexpressionwestern blotpurificationrecordssds pagealiquotsendotoxinmass spectrometryabsorbanceassays
26 articles
protein biochemistry
Activity assays versus abundance
Milligrams per millilitre are not enzyme units. Specific activity joins rate and mass, and a pure inactive protein differs from a crude active one.
8 October 2026 · 6 min read
protein biochemistry
Aggregation and cloudy protein samples
Cloudiness, a spin pellet or a void-volume peak means aggregated protein. Do not treat a turbid sample as a concentration or load it onto a column.
8 October 2026 · 7 min read
protein biochemistry
Bradford BCA and absorbance at 280 nm
Bradford, BCA and absorbance at 280 nm report different chemistries. Pick the assay your buffer allows and name the standard beside the number.
8 October 2026 · 8 min read
protein biochemistry
Codon use and insoluble expression
Why rare codons can slow translation, and why a codon table still does not prove that insoluble expression is a coding problem.
8 October 2026 · 7 min read
protein biochemistry
Comparing quantification assays for a lysate
Bradford, BCA and absorbance at 280 nm on a dirty lysate: which interference wins, why two kits disagree, and which standard to name.
8 October 2026 · 8 min read
protein biochemistry
Concentrating a dilute protein
How to choose ultrafiltration, precipitation or polymer dialysis when a protein is dilute, and why the smaller volume is not yet a concentration.
8 October 2026 · 8 min read
protein biochemistry
Detergents that ruin a later mass spec step
How SDS, Triton, NP-40 and Tween spoil a mass spectrum, which removal class to consider, and what to tell the person who will run it.
8 October 2026 · 9 min read
protein biochemistry
Dialysis desalting and buffer exchange
Dialysis, a desalting column and centrifugal exchange move a protein into a new buffer on different clocks. Check pH and conductivity after the swap.
8 October 2026 · 6 min read
protein biochemistry
Documenting a purification so it can be repeated
Which buffer pH, resin lot, gradient, gel, yield assay and tube location another person needs before a purification can be repeated.
8 October 2026 · 7 min read
protein biochemistry
Endotoxin is a separate question from purity
Why a clean SDS-PAGE lane leaves endotoxin unmeasured, when an LAL-class assay is the right extra question, and why removal is its own process.
8 October 2026 · 7 min read
protein biochemistry
Enzymes lose activity before they look degraded
An enzyme can lose activity while the Coomassie band remains. Oxidation, carryover, a missing cofactor or partial unfolding need an activity assay.
8 October 2026 · 7 min read