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PsychedeliaDokholyan Laboratory
TargetEnzymes

Cytochrome P450 1B1

Named enzymes, including the metabolising cytochromes and the monoamine oxidases.

Measurements
2
Compounds
2
Binding constants
2
Median pX
6.13

I · Identity

What this target is

Its function as UniProt states it, where in a cell the protein is found, and which cell types and tissues transcribe its gene.

Protein

CP1B1_HUMANCYP1B1Homo sapiens

Cytochrome P450 1B1

A cytochrome P450 monooxygenase involved in the metabolism of various endogenous substrates, including fatty acids, steroid hormones and vitamins10681376,11555828,12865317,15258110,20972997. Mechanistically, uses molecular oxygen inserting one oxygen atom into a substrate, and reducing the second into a water molecule, with two electrons provided by NADPH via cytochrome P450 reductase (NADPH--hemoprotein reductase)10681376,11555828,12865317,15258110,20972997. Exhibits catalytic activity for the formation of hydroxyestrogens from estrone (E1) and 17beta-estradiol (E2), namely 2- and 4-hydroxy E1 and E2. Displays a predominant hydroxylase activity toward E2 at the C-4 position11555828,12865317. Metabolizes testosterone and progesterone to B or D ring hydroxylated metabolites10426814. May act as a major enzyme for all-trans retinoic acid biosynthesis in extrahepatic tissues. Catalyzes two successive oxidative transformation of all-trans retinol to all-trans retinal and then to the active form all-trans retinoic acid10681376,15258110. Catalyzes the epoxidation of double bonds of certain PUFA. Converts arachidonic acid toward epoxyeicosatrienoic acid (EpETrE) regioisomers, 8,9-, 11,12-, and 14,15- EpETrE, that function as lipid mediators in the vascular system20972997. Additionally, displays dehydratase activity toward oxygenated eicosanoids hydroperoxyeicosatetraenoates (HpETEs). This activity is independent of cytochrome P450 reductase, NADPH, and O221068195. Also involved in the oxidative metabolism of xenobiotics, particularly converting polycyclic aromatic hydrocarbons and heterocyclic aryl amines procarcinogens to DNA-damaging products10426814. Plays an important role in retinal vascular development. Under hyperoxic O2 conditions, promotes retinal angiogenesis and capillary morphogenesis, likely by metabolizing the oxygenated products generated during the oxidative stress. Also, contributes to oxidative homeostasis and ultrastructural organization and function of trabecular meshwork tissue through modulation of POSTN expression (By similarity)

Quoted from UniProt’s FUNCTION annotation for Q16678 (reviewed). The superscript numbers are UniProt’s own PubMed citations, kept in the sentence and in order, each linking to the paper it names.

What it acts with

STRING’s highest-confidence human functional partners. The combined score mixes several kinds of evidence, so each channel is shown separately — a partner supported by experiment is a different claim from one supported only by text mining, and for a receptor this is where its coupling appears as evidence rather than as assertion.

PartnerCombinedExperimentDatabaseText mining
GSTP10.9730.0450.9000.722
COMT0.9710.0000.9000.719
EPHX10.9660.0690.9000.651
UGT1A60.9660.0000.9090.637
LRTOMT0.9660.0000.9000.669
UGT1A10.9630.0000.9090.598
UGT1A80.9630.0000.9090.598
UGT1A70.9630.0000.9090.598
UGT1A40.9630.0000.9090.598
UGT1A100.9630.0000.9090.599

Where it sits in the cell

  • Mitochondria

Human Protein Atlas, by antibody immunofluorescence in cell lines — a different assay from the expression figures below, which are RNA.

UniProt, curated Endoplasmic reticulum membrane · Microsome membrane · Mitochondrion

Expression by cell type

Single cell type RNA, the 12 highest of those the Human Protein Atlas reports for this gene. Transcript, not protein, and a cell type rather than a tissue.

  • Neutrophils373.6 nCPM
  • Fibroblasts273.1 nCPM
  • Pituicytes/FSCs256.8 nCPM
  • Endometrial secretory cells239.2 nCPM
  • Salivary duct cells203.5 nCPM
  • monocytes186 nCPM
  • Peritubular myoid cells183.6 nCPM
  • Leydig cells170.6 nCPM
  • Vascular endothelial cells167.2 nCPM
  • Decidual stromal cells160.5 nCPM
  • Urothelial cells157.4 nCPM
  • Smooth muscle cells153.4 nCPM

II · Anatomy

Where the gene is transcribed

The same two atlases the compound plates use, asked about this gene alone. Brain on the left, peripheral and autonomic tissues on the right.

Brain

cerebral cortex — 5.7 nTPM, from CYP1B1cerebellum — 1.0 nTPM, from CYP1B1hippocampal formation — 2.4 nTPM, from CYP1B1amygdala — 2.0 nTPM, from CYP1B1hypothalamus — 2.4 nTPM, from CYP1B1thalamus — no resolved target expressed herebasal ganglia — 5.1 nTPM, from CYP1B1medulla oblongata — no resolved target expressed here

basal ganglia: drawn as the caudate nucleus, putamen and globus pallidus.

Measured but not drawn — this anatomogram has no outline for them: pituitary gland 14.3, spinal cord 4.0, midbrain 2.7, retina 1.1.

Body

heart — 27.6 nTPM, from CYP1B1smooth muscle — 32.8 nTPM, from CYP1B1lung — 15.8 nTPM, from CYP1B1liver — 6.6 nTPM, from CYP1B1kidney — 22.5 nTPM, from CYP1B1stomach — 14.7 nTPM, from CYP1B1duodenum — 2.1 nTPM, from CYP1B1small intestine — 5.7 nTPM, from CYP1B1colon — 3.4 nTPM, from CYP1B1adrenal gland — 11.3 nTPM, from CYP1B1thyroid gland — 8.5 nTPM, from CYP1B1pancreas — 6.8 nTPM, from CYP1B1urinary bladder — 32.8 nTPM, from CYP1B1skeletal muscle — 3.4 nTPM, from CYP1B1spleen — 25.7 nTPM, from CYP1B1salivary gland — 4.0 nTPM, from CYP1B1
033 nTPM

Square-root ramp · shared scale across both plates

Shading is transcript level — not affinity, and not affinity combined with expression. Outlined but unshaded organs hold none of CYP1B1 transcript above the atlas’s detection threshold. Anatomy from EMBL-EBI Anatomogram (Apache License 2.0); regions identified by Uberon (uberon.org), CC BY 3.0.

Brain · 10

  • pituitary gland14.3 nTPM
  • cerebral cortex5.7 nTPM
  • basal ganglia5.1 nTPM
  • spinal cord4.0 nTPM
  • midbrain2.7 nTPM
  • hippocampal formation2.4 nTPM
  • hypothalamus2.4 nTPM
  • amygdala2.0 nTPM
  • retina1.1 nTPM
  • cerebellum1.0 nTPM

Peripheral and autonomic · 16

  • smooth muscle32.8 nTPM
  • urinary bladder32.8 nTPM
  • heart muscle27.6 nTPM
  • spleen25.7 nTPM
  • kidney22.5 nTPM
  • lung15.8 nTPM
  • stomach 114.7 nTPM
  • adrenal gland11.3 nTPM
  • thyroid gland8.5 nTPM
  • pancreas6.8 nTPM
  • liver6.6 nTPM
  • small intestine5.7 nTPM
  • salivary gland4.0 nTPM
  • colon3.4 nTPM
  • skeletal muscle3.4 nTPM
  • duodenum2.1 nTPM

Transcript is not protein. These are RNA levels for CYP1B1, shaded on √nTPM so that a three-order range stays legible — on a linear ramp every region but the strongest would read as blank, which looks like absence rather than less. A region carrying no shading is one the atlas reports no consensus value for, not one where the gene is silent. And a gene being transcribed somewhere is not evidence that any compound reaches it. Human Protein Atlas, RNA expression, nTPM (normalized transcripts per million), consensus tissue dataset.

III · Ranking

Compounds by strongest binding constant

One bar per compound: its strongest Ki or Kd at this target, expressed as pX. Compounds measured here only by a functional assay do not appear — they are in the table below.

  1. 01Cannabinol6.83
  2. 02Cannabidiol5.44

IV · Evidence

Every measurement at this target

Each row links to the ChEMBL assay it came from.

Equilibrium binding constants 2

Ki and Kd — a concentration at equilibrium. Directly comparable across rows at the same target.

TargetClassTypeValue (nM)pXOrganismAssay
Cytochrome P450 1B1EnzymesKi1486.83Homo sapiensCHEMBL4035358
Cytochrome P450 1B1EnzymesKi3,6305.44Homo sapiensCHEMBL4687719
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