dwb2023/gtopdb-target-family-interaction-detail huggingface dataset:
Target family: A1: Pepsin (type: enzyme)
Target: cathepsin D

Ligand: β-secretase inhibitor IV (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 6.349999904632568 pKi
Reference (Journal): Design, synthesis, and X-ray structure of potent memapsin 2 (beta-secretase) inhibitors with isophthalamide derivatives as the P2-P3-ligands.
Published in: J Med Chem

Ligand: compound 1 [PMID: 10498202] (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Median affinity: 9.2 pIC50
Reference (Journal): Synthesis and structure activity relationships of novel small molecule cathepsin D inhibitors.
Published in: Bioorg Med Chem Lett

Ligand: compound 33 [PMID: 32003991] (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 8.600000381469727 pIC50
Reference (Journal): Biomimetic Macrocyclic Inhibitors of Human Cathepsin D: Structure-Activity Relationship and Binding Mode Analysis.
Published in: J Med Chem

Ligand: compound 3 [PMID: 8410973] (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 7.739999771118164 pKi
Reference (Journal): Specificity in the binding of inhibitors to the active site of human/primate aspartic proteinases: analysis of P2-P1-P1'-P2' variation.
Published in: J Med Chem

Ligand: grassystatin A (Natural product)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 7.579999923706055 pIC50
Reference (Journal): Grassystatins A-C from marine cyanobacteria, potent cathepsin E inhibitors that reduce antigen presentation.
Published in: J Med Chem
Target family: A1: Pepsin (type: enzyme)
Target: cathepsin E

Ligand: compound 2 [PMID: 8410973] (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Median affinity: 10 pKi
Reference (Journal): Specificity in the binding of inhibitors to the active site of human/primate aspartic proteinases: analysis of P2-P1-P1'-P2' variation.
Published in: J Med Chem

Ligand: compound 3 [PMID: 8410973] (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 9.300000190734863 pKi
Reference (Journal): Specificity in the binding of inhibitors to the active site of human/primate aspartic proteinases: analysis of P2-P1-P1'-P2' variation.
Published in: J Med Chem

Ligand: grassystatin A (Natural product)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: yes
Median affinity: 9.050000190734863 pIC50
Reference (Journal): Grassystatins A-C from marine cyanobacteria, potent cathepsin E inhibitors that reduce antigen presentation.
Published in: J Med Chem
Target family: A1: Pepsin (type: enzyme)
Target: pepsinogen A5

Ligand: compound 3 [PMID: 8410973] (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 7.960000038146973 pKi
Reference (Journal): Specificity in the binding of inhibitors to the active site of human/primate aspartic proteinases: analysis of P2-P1-P1'-P2' variation.
Published in: J Med Chem
Target family: A1: Pepsin (type: enzyme)
Target: progastricsin

Ligand: compound 3 [PMID: 8410973] (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 9.050000190734863 pKi
Reference (Journal): Specificity in the binding of inhibitors to the active site of human/primate aspartic proteinases: analysis of P2-P1-P1'-P2' variation.
Published in: J Med Chem
Target family: A1: Pepsin (type: enzyme)
Target: renin

Ligand: aliskiren (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: yes
Approval source: EMA & FDA (2007)
Primary target: yes
Median affinity: 9.199999809265137 pIC50
Reference (Journal): Renin inhibition with aliskiren.
Published in: Clin Exp Pharmacol Physiol

Ligand: sitokiren (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 9.399999618530273 pIC50
Reference (Journal): Discovery of SPH3127: A Novel, Highly Potent, and Orally Active Direct Renin Inhibitor.
Published in: J Med Chem
Target family: A1: Pepsin (type: enzyme)
Target: beta-secretase 2

Ligand: AM-6494 (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 7.730000019073486 pIC50
Reference (Journal): Discovery of AM-6494: A Potent and Orally Efficacious β-Site Amyloid Precursor Protein Cleaving Enzyme 1 (BACE1) Inhibitor with in Vivo Selectivity over BACE2.
Published in: J Med Chem

Ligand: atabecestat (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 8.020000457763672 pKi
Reference (Journal): Discovery of Extremely Selective Fused Pyridine-Derived β-Site Amyloid Precursor Protein-Cleaving Enzyme (BACE1) Inhibitors with High In Vivo Efficacy through 10s Loop Interactions.
Published in: J Med Chem

Ligand: β-secretase inhibitor IV (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 6.619999885559082 pKi
Reference (Journal): Design, synthesis, and X-ray structure of potent memapsin 2 (beta-secretase) inhibitors with isophthalamide derivatives as the P2-P3-ligands.
Published in: J Med Chem

Ligand: compound 3l [PMID: 30637955] (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 8.800000190734863 pKi
Reference (Journal): Highly Selective and Potent Human β-Secretase 2 (BACE2) Inhibitors against Type 2 Diabetes: Design, Synthesis, X-ray Structure and Structure-Activity Relationship Studies.
Published in: ChemMedChem

Ligand: compound 6 [PMID: 34553947] (Synthetic organic)
Interaction type: Inhibitor
Action: None
Ligand approved: no
Primary target: no
Median affinity: 6.730000019073486 pKi
Reference (Journal): Discovery of Extremely Selective Fused Pyridine-Derived β-Site Amyloid Precursor Protein-Cleaving Enzyme (BACE1) Inhibitors with High In Vivo Efficacy through 10s Loop Interactions.
Published in: J Med Chem

Ligand: compound J [PMID: 21907142] (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 8.220000267028809 pIC50
Reference (Journal): Bace2 is a β cell-enriched protease that regulates pancreatic β cell function and mass.
Published in: Cell Metab

Ligand: example 20 [WO2010128058] (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: yes
Median affinity: 8.220000267028809 pIC50
Reference (Patent): Dihydropyrimidinones for use as BACE2 inhibitors.
Target family: AAA ATPases (type: enzyme)
Target: lon peptidase 1, mitochondrial

Ligand: compound 12d [PMID: 33821636] (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 7.769999980926514 pIC50
Reference (Journal): Structure-Based Design of Selective LONP1 Inhibitors for Probing <i>In Vitro</i> Biology.
Published in: J Med Chem
Target family: AAA ATPases (type: enzyme)
Target: caseinolytic mitochondrial matrix peptidase proteolytic subunit

Ligand: ONC201 (Synthetic organic)
Interaction type: Allosteric modulator
Action: Activation
Ligand approved: no
Primary target: no
Median affinity:  -
Reference (Journal): ONC201 and imipridones: Anti-cancer compounds with clinical efficacy.
Published in: Neoplasia

Ligand: compound 16z [PMID: 35609303] (Synthetic organic)
Interaction type: Activator
Action: Activation
Ligand approved: no
Primary target: no
Median affinity: 6.699999809265137 pEC50
Reference (Journal): Discovery of a Novel Series of Imipridone Compounds as <i>Homo sapiens</i> Caseinolytic Protease P Agonists with Potent Antitumor Activities In Vitro and In Vivo.
Published in: J Med Chem
Target family: ABCA subfamily (type: transporter)
Target: ABCA1

Ligand: bihelical apoA-I mimetic peptide 5A (Peptide)
Interaction type: None
Action: Binding
Ligand approved: no
Primary target: no
Median affinity:  -
Reference (Journal): Asymmetry in the lipid affinity of bihelical amphipathic peptides. A structural determinant for the specificity of ABCA1-dependent cholesterol efflux by peptides.
Published in: J Biol Chem

Ligand: probucol (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: yes
Approval source: FDA (1977)
Primary target: yes
Median affinity:  -
Reference (Journal): Probucol inhibits ABCA1-mediated cellular lipid efflux.
Published in: Arterioscler Thromb Vasc Biol

Ligand: probucol (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: yes
Approval source: FDA (1977)
Primary target: yes
Median affinity:  -
Reference (Journal): Probucol inactivates ABCA1 in the plasma membrane with respect to its mediation of apolipoprotein binding and high density lipoprotein assembly and to its proteolytic degradation.
Published in: J Biol Chem
Target family: ABCB subfamily (type: transporter)
Target: ABCB1

Ligand: biricodar (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 5.300000190734863 pIC50
Reference (Journal): Studies on quinazolinones as dual inhibitors of Pgp and MRP1 in multidrug resistance.
Published in: Bioorg Med Chem Lett

Ligand: zosuquidar (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 7.230000019073486 pKi
Reference (Journal): Selectivity of the multidrug resistance modulator, LY335979, for P-glycoprotein and effect on cytochrome P-450 activities.
Published in: J Pharmacol Exp Ther
Target family: ABCB subfamily (type: transporter)
Target: ABCB11

Ligand: glycochenodeoxycholic acid (Metabolite)
Interaction type: None
Action: Binding
Ligand approved: no
Primary target: no
Median affinity: 5.150000095367432 pKi
Reference (Journal): The human bile salt export pump: characterization of substrate specificity and identification of inhibitors.
Published in: Gastroenterology
Target family: ABCB subfamily (type: transporter)
Target: ABCB1

Ligand: WS-898 (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 8.300000190734863 pIC50
Reference (Journal): Discovery of the Triazolo[1,5-<i>a</i>]Pyrimidine-Based Derivative WS-898 as a Highly Efficacious and Orally Bioavailable ABCB1 Inhibitor Capable of Overcoming Multidrug Resistance.
Published in: J Med Chem

Ligand: valspodar (Peptide)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 5.889999866485596 pKi
Reference (Journal): PSC833, cyclosporin A, and dexniguldipine effects on cellular calcein retention and inhibition of the multidrug resistance pump in human leukemic lymphoblasts.
Published in: Biochem Biophys Res Commun

Ligand: tariquidar (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 7.420000076293945 pIC50
Reference (Journal): Reversal of P-glycoprotein mediated multidrug resistance by novel anthranilamide derivatives.
Published in: Bioorg Med Chem Lett

Ligand: encequidar (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 7.28000020980835 pIC50
Reference (Journal): Discovery of Encequidar, First-in-Class Intestine Specific P-glycoprotein Inhibitor.
Published in: J Med Chem

Ligand: compound 14 [PMID: 30925062] (Synthetic organic)
Interaction type: Inhibitor
Action: Competitive
Ligand approved: no
Primary target: no
Median affinity: 5.760000228881836 pIC50
Reference (Journal): Identification of Thienopyrimidine Scaffold as an Inhibitor of the ABC Transport Protein ABCC1 (MRP1) and Related Transporters Using a Combined Virtual Screening Approach.
Published in: J Med Chem

Ligand: compound 14 [PMID: 30925062] (Synthetic organic)
Interaction type: Inhibitor
Action: Competitive
Ligand approved: no
Primary target: no
Median affinity: 6.170000076293945 pIC50
Reference (Journal): Identification of Thienopyrimidine Scaffold as an Inhibitor of the ABC Transport Protein ABCC1 (MRP1) and Related Transporters Using a Combined Virtual Screening Approach.
Published in: J Med Chem
Target family: ABCC subfamily (type: transporter)
Target: ATP-binding cassette, sub-family C (CFTR/MRP), member 8

Ligand: chlorpropamide (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: yes
Approval source: FDA (1958)
Primary target: no
Median affinity:  -
Target family: ABCC subfamily (type: transporter)
Target: ABCC2

Ligand: PAK-104P (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 5.429999828338623 pKi
Reference (Journal): Effect of multidrug resistance-reversing agents on transporting activity of human canalicular multispecific organic anion transporter.
Published in: Mol Pharmacol
Target family: ABCC subfamily (type: transporter)
Target: ABCC4

Ligand: estradiol disulfate (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 6.699999809265137 pIC50
Reference (Journal): Steroid and bile acid conjugates are substrates of human multidrug-resistance protein (MRP) 4 (ATP-binding cassette C4).
Published in: Biochem J
Target family: ABCC subfamily (type: transporter)
Target: ABCC1

Ligand: WP814 (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 7.150000095367432 pKi
Reference (Journal): Doxorubicin- and daunorubicin-glutathione conjugates, but not unconjugated drugs, competitively inhibit leukotriene C4 transport mediated by MRP/GS-X pump.
Published in: Biochem Biophys Res Commun

Ligand: compound 14 [PMID: 30925062] (Synthetic organic)
Interaction type: Inhibitor
Action: Competitive
Ligand approved: no
Primary target: no
Median affinity: 5.300000190734863 pIC50
Reference (Journal): Identification of Thienopyrimidine Scaffold as an Inhibitor of the ABC Transport Protein ABCC1 (MRP1) and Related Transporters Using a Combined Virtual Screening Approach.
Published in: J Med Chem

Ligand: biricodar (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 5.289999961853027 pIC50
Reference (Journal): Studies on quinazolinones as dual inhibitors of Pgp and MRP1 in multidrug resistance.
Published in: Bioorg Med Chem Lett
Target family: ABCC subfamily (type: transporter)
Target: ABCC5

Ligand: compound 2 [PMID: 22380603] (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 7.190000057220459 pKi
Reference (Journal): Novel cGMP efflux inhibitors identified by virtual ligand screening (VLS) and confirmed by experimental studies.
Published in: J Med Chem

Ligand: sildenafil (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: yes
Approval source: EMA & FDA (1998)
Primary target: no
Median affinity: 5.920000076293945 pKi
Reference (Journal): Novel cGMP efflux inhibitors identified by virtual ligand screening (VLS) and confirmed by experimental studies.
Published in: J Med Chem
Target family: ABCC subfamily (type: transporter)
Target: ABCC9

Ligand: compound 13b [PMID: 19101153] (Synthetic organic)
Interaction type: Allosteric modulator
Action: Positive
Ligand approved: no
Primary target: no
Median affinity: 6.170000076293945 pEC50
Reference (Journal): Discovery and structure-activity relationships of a novel series of benzopyran-based K(ATP) openers for urge urinary incontinence.
Published in: Bioorg Med Chem
Target family: ABCC subfamily (type: transporter)
Target: ATP-binding cassette, sub-family C (CFTR/MRP), member 8

Ligand: repaglinide (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: yes
Approval source: FDA (1997), EMA (1998)
Primary target: yes
Median affinity: 6.96999979019165 pIC50
Reference (Journal): Synthesis and in vitro evaluation of (S)-2-([11C]methoxy)-4-[3-methyl-1-(2-piperidine-1-yl-phenyl)-butyl-carbamoyl]-benzoic acid ([11C]methoxy-repaglinide): a potential beta-cell imaging agent.
Published in: Bioorg Med Chem Lett
Target family: ABCG subfamily (type: transporter)
Target: ABCG2

Ligand: KS 176 (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 6.230000019073486 pIC50

Ligand: Ko 143 (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity:  -

Ligand: Fumitremorgin C (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity:  -

Ligand: cyclosporin A (Peptide)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: yes
Approval source: FDA and UK (1983), EMA (2015)
Primary target: no
Median affinity: 6.300000190734863 pKi
Reference (Journal): Functional characterization of the human multidrug transporter, ABCG2, expressed in insect cells.
Published in: Biochem Biophys Res Commun

Ligand: compound 14 [PMID: 30925062] (Synthetic organic)
Interaction type: Inhibitor
Action: Non-competitive
Ligand approved: no
Primary target: no
Median affinity: 5.619999885559082 pIC50
Reference (Journal): Identification of Thienopyrimidine Scaffold as an Inhibitor of the ABC Transport Protein ABCC1 (MRP1) and Related Transporters Using a Combined Virtual Screening Approach.
Published in: J Med Chem
Target family: Abl family (type: enzyme)
Target: ABL proto-oncogene 2, non-receptor tyrosine kinase

Ligand: compound 24 [PMID: 23441572] (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity:  pIC50
Reference (Journal): Rapid discovery of a novel series of Abl kinase inhibitors by application of an integrated microfluidic synthesis and screening platform.
Published in: J Med Chem

Ligand: pexmetinib (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 8 pIC50
Reference (Journal): Pexmetinib: A Novel Dual Inhibitor of Tie2 and p38 MAPK with Efficacy in Preclinical Models of Myelodysplastic Syndromes and Acute Myeloid Leukemia.
Published in: Cancer Res
Target family: Abl family (type: enzyme)
Target: ABL proto-oncogene 1, non-receptor tyrosine kinase

Ligand: olverembatinib (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: yes
Approval source: China (2021)
Primary target: no
Median affinity: 9.489999771118164 pKd
Reference (Journal): Identification of GZD824 as an orally bioavailable inhibitor that targets phosphorylated and nonphosphorylated breakpoint cluster region-Abelson (Bcr-Abl) kinase and overcomes clinically acquired mutation-induced resistance against imatinib.
Published in: J Med Chem
Target family: Abl family (type: enzyme)
Target: ABL proto-oncogene 2, non-receptor tyrosine kinase

Ligand: risvodetinib (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 7.110000133514404 pIC50
Reference (Patent): Compositions and methods for inhibiting kinases
Target family: Abscisic acid receptor complex (type: other_protein)
Target: LanC like 2

Ligand: omilancor (Synthetic organic)
Interaction type: None
Action: Binding
Ligand approved: no
Primary target: no
Median affinity: 5.110000133514404 pKd
Reference (Journal): An N,N-Bis(benzimidazolylpicolinoyl)piperazine (BT-11): A Novel Lanthionine Synthetase C-Like 2-Based Therapeutic for Inflammatory Bowel Disease.
Published in: J Med Chem
Target family: Abscisic acid receptor complex (type: other_protein)
Target: CD38

Ligand: daratumumab (Antibody)
Interaction type: Antibody
Action: Antagonist
Ligand approved: yes
Approval source: FDA (2015), EMA (2017)
Primary target: yes
Median affinity: 8.220000267028809 pKd
Reference (Patent): Antibodies Against Cd38 For Treatment Of Multiple Myeloma.

Ligand: isatuximab (Antibody)
Interaction type: Antibody
Action: Binding
Ligand approved: yes
Approval source: EMA & FDA (2020)
Primary target: yes
Median affinity:  pKd
Reference (Patent): Novel anti-cd38 antibodies for the treatment of cancer.

Ligand: mezagitamab (Antibody)
Interaction type: Antibody
Action: Binding
Ligand approved: no
Primary target: no
Median affinity: 8.260000228881836 pKd
Reference (Patent): Anti-cd38 antibodies

Ligand: MK-0159 (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 8.520000457763672 pIC50
Reference (Journal): Orally Bioavailable Enzymatic Inhibitor of CD38, <b>MK-0159</b>, Protects against Ischemia/Reperfusion Injury in the Murine Heart.
Published in: J Med Chem

Ligand: MK-0159 (Synthetic organic)
Interaction type: Inhibitor
Action: Inhibition
Ligand approved: no
Primary target: no
Median affinity: 7.659999847412109 pIC50
Reference (Journal): Orally Bioavailable Enzymatic Inhibitor of CD38, <b>MK-0159</b>, Protects against Ischemia/Reperfusion Injury in the Murine Heart.
Published in: J Med Chem
Target family: Abscisic acid receptor complex (type: other_protein)
Target: LanC like 2

Ligand: abscisic acid (Natural product)
Interaction type: None
Action: Binding
Ligand approved: no
Primary target: no
Median affinity: 7.960000038146973 pKd
Reference (Journal): Abscisic acid is an endogenous cytokine in human granulocytes with cyclic ADP-ribose as second messenger.
Published in: Proc Natl Acad Sci USA

Ligand: NSC61610 (Synthetic organic)
Interaction type: None
Action: Binding
Ligand approved: no
Primary target: no
Median affinity:  -
Reference (Journal): Computational modeling-based discovery of novel classes of anti-inflammatory drugs that target lanthionine synthetase C-like protein 2.
Published in: PLoS ONE

Ligand: NSC61610 (Synthetic organic)
Interaction type: None
Action: Binding
Ligand approved: no
Primary target: no
Median affinity:  -
Reference (Journal): An N,N-Bis(benzimidazolylpicolinoyl)piperazine (BT-11): A Novel Lanthionine Synthetase C-Like 2-Based Therapeutic for Inflammatory Bowel Disease.
Published in: J Med Chem