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G4505 Sigma-Aldrich

Guanidine hydrochloride

organic base and chaeotropic agent, ≥99% (titration)

Synonym: Aminoformamidine hydrochloride, Aminomethanamidine hydrochloride, Guanidinium chloride

  • CAS Number 50-01-1

  • Linear Formula NH2C(=NH)NH2 · HCl

  • Molecular Weight 95.53

  •  Beilstein/REAXYS Number 3591990

  •  EC Number 200-002-3

  •  MDL number MFCD00013026

  •  PubChem Substance ID 24895176



Related Categories Biochemicals and Reagents, Chaotropic Agents, Core Bioreagents, Denaturation, Nucleosides and Nucleotides,
Quality Level   300
biological source   synthetic (organic)
assay   ≥99% (titration)
form   crystalline powder
application(s)   RNA extraction: suitable
impurities   ≤0.3% water (Karl Fischer)
color   white
pH   (25 °C, 4.6 - 6 at 573 g/L)
mp   180-185 °C (lit.)
solubility   H2O: 6 M
density   1.3 g/cm3 (lit.)
absorption   ≤0.10 at 260 nm in H2O at 6 M
SMILES string   Cl[H].NC(N)=N
InChI   1S/CH5N3.ClH/c2-1(3)4;/h(H5,2,3,4);1H
Gene Information   human ... KCNA1(3736), KCNA10(3744), KCNA2(3737), KCNA3(3738), KCNA4(3739), KCNA5(3741), KCNA6(3742), KCNA7(3743), KCNB1(3745), KCNB2(9312), KCNC1(3746), KCNC2(3747), KCNC3(3748), KCNC4(3749), KCND1(3750), KCND2(3751), KCND3(3752), KCNF1(3754), KCNG1(3755), KCNG2(26251), KCNG3(170850), KCNG4(93107), KCNH1(3756), KCNH2(3757), KCNH3(23416), KCNH4(23415), KCNH5(27133), KCNH6(81033), KCNH7(90134), KCNH8(131096), KCNQ1(3784), KCNQ2(3785), KCNQ3(3786), KCNQ4(9132), KCNQ5(56479), KCNS1(3787), KCNS2(3788), KCNS3(3790), KCNV1(27012), KCNV2(169522)



Guanidine hydrochloride (GdnHCl) has been used:
• to perform absolute quantitation of amyloid-beta (Aß) isoforms in plasma
• in protein carbonylation assay
• for the quantification of glycosaminoglycans (GAG)
• for denaturation of cow’s milk allergens
• as a control in antiviral screening tests with coxsackievirus B3 (CVB3)
• in RNA isolation to dissociate nucleoproteins and inhibit RNase

Strong chaotropic agent useful for the denaturation and subsequent refolding of proteins. This strong denaturant can solubilize insoluble or denatured proteins such as inclusion bodies. This can be used as the first step in refolding proteins or enzymes into their active form. Urea and dithiothreitol (DTT) may also be necessary.


1 kg in poly bottle

2, 10, 25 kg in poly drum

25, 100, 500 g in poly bottle

Biochem/physiol Actions

Guanidine hydrochloride (GdnHCl) is hydroscopic and a small molecule. It is a potent denaturant of enzymes, which results in conformational changes in the enzyme, leading to complete loss of enzyme activity. GdnHCl is involved in blocking the activity of heat shock protein 104 (Hsp104) adenosine triphosphatase (ATPase) in vivo. It is involved in denaturing alkaline phosphatase (ALPase) in Haliotis diversicolor. GdnHCl leads to the deactivation of enzymes like papain and aminoacylase. GdnHCl, at higher concentrations, is effective in virus inactivation, such as herpes simplex virus 1 (HSV-1).


May agglomerate upon storage. The quality of the product does not appear to be affected and solutions prepared from the free-flowing and lumpy guanidine hydrochloride appear identical. For free-flowing material, please see our Redi-Dri free-flowing product number RDD001.

Preparation Note

In order to make an 8M solution in water, one must heat the solution to 35 °C for approximately 30 minutes.
The maximum solubility of guanidine hydrochloride in water at room temperature is approximately 6M.

Legal Information

Redi-Dri is a trademark of Sigma-Aldrich Co. LLC

Safety & Documentation

Safety Information

GHS07  GHS07
Signal word 
Hazard statements 
Personal Protective Equipment 
NONH for all modes of transport
WGK Germany 
Flash Point(F) 
Not applicable
Flash Point(C) 
Not applicable


Certificate of Analysis (COA)

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Certificate of Origin (COO)

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pHast Pack
Protocols & Articles
Peer-Reviewed Papers


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G4505 Guanidine hydrochloride, organic base and chaeotropic agent, ≥99% (titration)

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