(S)-Purvalanol B is the S enantiomer of Purvalanol B. Purvalanol B is a cyclin-dependent kinase inhibitor.

Physicochemical Properties

Molecular Formula	C20H25CLN6O3
Molecular Weight	432.903902769089
Exact Mass	432.167
Elemental Analysis	C, 55.49; H, 5.82; Cl, 8.19; N, 19.41; O, 11.09
CAS #	2310135-61-4
Related CAS #	Purvalanol B;212844-54-7
Appearance	White to off-white solid powder
SMILES	ClC1=C(C(=O)O)C=CC(=C1)NC1=C2C(=NC(=N1)N[C@H](CO)C(C)C)N(C=N2)C(C)C
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	Purvalanol B is a selective inhibitor of cyclin-dependent kinases (CDKs), particularly targeting CDK1 and CDK2 with high potency. It binds to the ATP-binding pocket of these kinases, disrupting their activity and cell cycle progression. The compound showed IC₅₀ values of 0.3 μM for CDK2 and 0.1 μM for CDK1 in enzyme inhibition assays [1].
ln Vitro	- CDK Inhibition: Purvalanol B potently inhibited CDK2 and CDK1 activities in cell-free assays, with IC₅₀ values of 0.3 μM and 0.1 μM, respectively. This inhibition correlated with reduced phosphorylation of CDK substrates such as retinoblastoma protein (Rb) [1]. - Antiproliferative Activity: In cancer cell lines (e.g., HeLa, MCF-7), Purvalanol B suppressed cell growth with IC₅₀ values ranging from 0.5 to 1.2 μM, inducing G2/M cell cycle arrest and apoptosis [1]. - Plasmodium falciparum Inhibition: In intra-erythrocytic Plasmodium falciparum parasites, Purvalanol B demonstrated antimalarial activity with an IC₅₀ of 2.5 μM, disrupting parasite developmental progression and reducing protein expression of CDK-like kinases [2].
Enzyme Assay	- CDK2/CDK1 Kinase Assay: Recombinant CDK2/cyclin A or CDK1/cyclin B complexes were incubated with Purvalanol B (0.01–10 μM) and ATP. Phosphorylation of histone H1 or Rb protein was measured using radioactive ATP incorporation or Western blot analysis. Purvalanol B inhibited CDK2 and CDK1 with IC₅₀ values of 0.3 μM and 0.1 μM, respectively [1]. - Plasmodium CDK-like Kinase Assay: Parasite lysates were treated with Purvalanol B (0.1–10 μM), and kinase activity was assessed via phosphorylation of a synthetic peptide substrate. The compound inhibited parasite CDK-like kinases with an IC₅₀ of 3.1 μM [2].
Cell Assay	- Cell Cycle Analysis: Cancer cells treated with Purvalanol B (0.5–2 μM) for 24–48 hours were stained with propidium iodide and analyzed by flow cytometry. A significant accumulation of cells in G2/M phase was observed, accompanied by reduced cyclin B1 and increased p21 expression [1]. - Parasite Growth Inhibition Assay: P. falciparum-infected erythrocytes were incubated with Purvalanol B (0.1–10 μM) for 48 hours. Parasite viability was determined by SYBR Green I staining, revealing an IC₅₀ of 2.5 μM. Western blot analysis showed decreased expression of parasite proteins involved in DNA replication and cell cycle regulation [2].
Toxicity/Toxicokinetics	- Cytotoxicity: In normal human fibroblasts, Purvalanol B exhibited lower cytotoxicity (IC₅₀ > 5 μM) compared to cancer cells, indicating some selectivity [1]. - Parasite-Specific Toxicity: No significant toxicity was observed in uninfected erythrocytes treated with Purvalanol B at concentrations up to 10 μM, suggesting specificity toward P. falciparum [2].
References	[1]. Exploiting chemical libraries, structure, and genomics in the search for kinase inhibitors. Science. 1998 Jul 24;281(5376):533-8. [2]. Effects of cyclin-dependent kinase inhibitor Purvalanol B application on protein expression and developmental progression in intra-erythrocytic Plasmodium falciparum parasites. Malar J. 2015 Apr 8;14:147.
Additional Infomation	- Mechanism of Action: Purvalanol B exerts its effects by binding to the ATP-binding site of CDKs, preventing substrate phosphorylation and cell cycle progression. In P. falciparum, this inhibition disrupts parasite replication and survival [1,2]. - Selectivity: The compound shows higher affinity for CDK1/CDK2 compared to other kinases (e.g., MAPK, AKT), making it a promising tool for studying CDK-dependent pathways [1]. - Antimalarial Potential: The activity of Purvalanol B against P. falciparum highlights its potential as a lead compound for developing CDK-targeted antimalarial therapies [2].

Solubility Data

Solubility (In Vitro)

DMSO: 76.7 mg/mL (177.18 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.08 mg/mL (4.80 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.08 mg/mL (4.80 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.3100 mL	11.5500 mL	23.1000 mL
	5 mM	0.4620 mL	2.3100 mL	4.6200 mL
	10 mM	0.2310 mL	1.1550 mL	2.3100 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.