Guanidine hydrochloride solution has been used:

• for protein denaturation
• to homogenize hypothalamus, thalamus, prefrontal cortex, and brainstem samples for total β-amyloid (Aβ) extraction and Aβ42 quantification
• as a chaotropic denaturant to treat human immunodeficiency virus-1 (HIV-1) samples to study its effects on HIV-1 sensitivity and to assay protein stability

Guanidine‐HCl (Gnd-HCl), an efficient chaotropic agent, is broadly used in RNA isolation, globular protein denaturation, and protein refolding studies as a denaturant. It is an appropriate sample buffer for the quick and effective elution of affinity-purified protein complexes and the subsequent protein digestion step. GnHCl can be used to extract proteins in extracellular matrix (ECM)‐rich tissues including bone, cartilage, ligament, and tendon. Gnd-HCl is not used in proteomics experiments due to its interference with trypsin activity at low molar concentrations and tendency to precipitate when combined with sodium dodecyl sulfate (SDS). It is appropriate for performing rapid and single-step affinity-purification mass spectrometry (AP-MS) experiments.