(4S)-4-[[(2S)-5-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-5-amino-2-[[(2S,3S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-amino-3-carboxypropanoyl]amino]-4-methylsulfanylbutanoyl]pyrrolidine-2-carbonyl]amino]-3-methylpentanoyl]amino]-5-oxopentanoyl]amino]propanoyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-5-oxopentanoyl]amino]-5-[(2S)-2-[[(2S)-1-[[(2S)-1-[[2-[(2S)-2-[[(2S)-1-[[(1S)-4-carbamimidamido-1-carboxybutyl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-2-oxoethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-5-oxopentanoic acid

C102H160N24O27S — CID 177449429

About (4S)-4-[[(2S)-5-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-5-amino-2-[[(2S,3S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-amino-3-carboxypropanoyl]amino]-4-methylsulfanylbutanoyl]pyrrolidine-2-carbonyl]amino]-3-methylpentanoyl]amino]-5-oxopentanoyl]amino]propanoyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-5-oxopentanoyl]amino]-5-[(2S)-2-[[(2S)-1-[[(2S)-1-[[2-[(2S)-2-[[(2S)-1-[[(1S)-4-carbamimidamido-1-carboxybutyl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-2-oxoethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-5-oxopentanoic acid

(4S)-4-[[(2S)-5-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-5-amino-2-[[(2S,3S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-amino-3-carboxypropanoyl]amino]-4-methylsulfanylbutanoyl]pyrrolidine-2-carbonyl]amino]-3-methylpentanoyl]amino]-5-oxopentanoyl]amino]propanoyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-5-oxopentanoyl]amino]-5-[(2S)-2-[[(2S)-1-[[(2S)-1-[[2-[(2S)-2-[[(2S)-1-[[(1S)-4-carbamimidamido-1-carboxybutyl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-2-oxoethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-5-oxopentanoic acid (PubChem CID 177449429) has the molecular formula C102H160N24O27S and a molecular weight of 2186.61 g/mol. Its IUPAC name is (4S)-4-[[(2S)-5-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-5-amino-2-[[(2S,3S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-amino-3-carboxypropanoyl]amino]-4-methylsulfanylbutanoyl]pyrrolidine-2-carbonyl]amino]-3-methylpentanoyl]amino]-5-oxopentanoyl]amino]propanoyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-5-oxopentanoyl]amino]-5-[(2S)-2-[[(2S)-1-[[(2S)-1-[[2-[(2S)-2-[[(2S)-1-[[(1S)-4-carbamimidamido-1-carboxybutyl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-2-oxoethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-5-oxopentanoic acid.

Molecular Properties

• Compound Name: (4S)-4-[[(2S)-5-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-5-amino-2-[[(2S,3S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-amino-3-carboxypropanoyl]amino]-4-methylsulfanylbutanoyl]pyrrolidine-2-carbonyl]amino]-3-methylpentanoyl]amino]-5-oxopentanoyl]amino]propanoyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-5-oxopentanoyl]amino]-5-[(2S)-2-[[(2S)-1-[[(2S)-1-[[2-[(2S)-2-[[(2S)-1-[[(1S)-4-carbamimidamido-1-carboxybutyl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-2-oxoethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-5-oxopentanoic acid
• PubChem CID: 177449429
• Molecular Formula: C102H160N24O27S
• Molecular Weight: 2186.61 g/mol
• Exact Mass: 2185.16
• IUPAC Name: (4S)-4-[[(2S)-5-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-5-amino-2-[[(2S,3S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-amino-3-carboxypropanoyl]amino]-4-methylsulfanylbutanoyl]pyrrolidine-2-carbonyl]amino]-3-methylpentanoyl]amino]-5-oxopentanoyl]amino]propanoyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-5-oxopentanoyl]amino]-5-[(2S)-2-[[(2S)-1-[[(2S)-1-[[2-[(2S)-2-[[(2S)-1-[[(1S)-4-carbamimidamido-1-carboxybutyl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-2-oxoethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-5-oxopentanoic acid
• SMILES: [H]/N=C(\N)NCCC[C@H](NC(=O)[C@@H](NC(=O)[C@@H]1CCCN1C(=O)CNC(=O)[C@H](CC(C)C)NC(=O)[C@@H](NC(=O)[C@@H]1CCCN1C(=O)[C@H](CCC(=O)O)NC(=O)[C@H](CCC(N)=O)NC(=O)[C@H](Cc1ccc(O)cc1)NC(=O)[C@H](CC(C)C)NC(=O)[C@H](CC(C)C)NC(=O)[C@H](Cc1ccccc1)NC(=O)[C@H](C)NC(=O)[C@H](CCC(N)=O)NC(=O)[C@@H](NC(=O)[C@@H]1CCCN1C(=O)[C@H](CCSC)NC(=O)[C@@H](N)CC(=O)O)[C@@H](C)CC)C(C)C)C(C)C)C(=O)O
• InChI: InChI=1S/C102H160N24O27S/c1-15-57(12)83(123-95(146)75-28-22-43-126(75)100(151)66(39-44-154-14)113-85(136)62(103)50-80(133)134)98(149)112-63(33-36-76(104)128)87(138)110-58(13)84(135)116-71(48-59-23-17-16-18-24-59)92(143)118-69(46-53(4)5)89(140)117-70(47-54(6)7)90(141)119-72(49-60-29-31-61(127)32-30-60)91(142)111-64(34-37-77(105)129)88(139)114-65(35-38-79(131)132)99(150)125-42-21-27-74(125)94(145)122-82(56(10)11)97(148)120-68(45-52(2)3)86(137)109-51-78(130)124-41-20-26-73(124)93(144)121-81(55(8)9)96(147)115-67(101(152)153)25-19-40-108-102(106)107/h16-18,23-24,29-32,52-58,62-75,81-83,127H,15,19-22,25-28,33-51,103H2,1-14H3,(H2,104,128)(H2,105,129)(H,109,137)(H,110,138)(H,111,142)(H,112,149)(H,113,136)(H,114,139)(H,115,147)(H,116,135)(H,117,140)(H,118,143)(H,119,141)(H,120,148)(H,121,144)(H,122,145)(H,123,146)(H,131,132)(H,133,134)(H,152,153)(H4,106,107,108)/t57-,58-,62-,63-,64-,65-,66-,67-,68-,69-,70-,71-,72-,73-,74-,75-,81-,82-,83-/m0/s1
• InChIKey: VFGLVSFVDXLRBB-YDBUNGCJSA-N
• XLogP: -3.13
• TPSA: 803.66 Ų
• H-Bond Donors: 25
• H-Bond Acceptors: 27
• Rotatable Bonds: 66
• Heavy Atoms: 154
• Complexity: —

Lipinski Rule of Five

3 violations

Rule	Value
MW ≤ 500	2186.61
LogP ≤ 5	-3.13
H-Bond Donors ≤ 5	25
H-Bond Acceptors ≤ 10	27

Computed Properties (RDKit)

• Structural Alerts: {'alert_name': 'Aliphatic_long_chain', 'substructure': 'N/A'}, {'alert_name': 'imine_1', 'substructure': 'N/A'}, {'alert_name': 'imine_2', 'substructure': 'N/A'}

Frequently Asked Questions

What is the IUPAC name of (4S)-4-[[(2S)-5-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-5-amino-2-[[(2S,3S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-amino-3-carboxypropanoyl]amino]-4-methylsulfanylbutanoyl]pyrrolidine-2-carbonyl]amino]-3-methylpentanoyl]amino]-5-oxopentanoyl]amino]propanoyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-5-oxopentanoyl]amino]-5-[(2S)-2-[[(2S)-1-[[(2S)-1-[[2-[(2S)-2-[[(2S)-1-[[(1S)-4-carbamimidamido-1-carboxybutyl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-2-oxoethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-5-oxopentanoic acid?

The IUPAC name of (4S)-4-[[(2S)-5-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-5-amino-2-[[(2S,3S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-amino-3-carboxypropanoyl]amino]-4-methylsulfanylbutanoyl]pyrrolidine-2-carbonyl]amino]-3-methylpentanoyl]amino]-5-oxopentanoyl]amino]propanoyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-5-oxopentanoyl]amino]-5-[(2S)-2-[[(2S)-1-[[(2S)-1-[[2-[(2S)-2-[[(2S)-1-[[(1S)-4-carbamimidamido-1-carboxybutyl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-2-oxoethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-5-oxopentanoic acid (CID 177449429) is (4S)-4-[[(2S)-5-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-5-amino-2-[[(2S,3S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-amino-3-carboxypropanoyl]amino]-4-methylsulfanylbutanoyl]pyrrolidine-2-carbonyl]amino]-3-methylpentanoyl]amino]-5-oxopentanoyl]amino]propanoyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-5-oxopentanoyl]amino]-5-[(2S)-2-[[(2S)-1-[[(2S)-1-[[2-[(2S)-2-[[(2S)-1-[[(1S)-4-carbamimidamido-1-carboxybutyl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-2-oxoethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-5-oxopentanoic acid.

What is the SMILES notation for (4S)-4-[[(2S)-5-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-5-amino-2-[[(2S,3S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-amino-3-carboxypropanoyl]amino]-4-methylsulfanylbutanoyl]pyrrolidine-2-carbonyl]amino]-3-methylpentanoyl]amino]-5-oxopentanoyl]amino]propanoyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-5-oxopentanoyl]amino]-5-[(2S)-2-[[(2S)-1-[[(2S)-1-[[2-[(2S)-2-[[(2S)-1-[[(1S)-4-carbamimidamido-1-carboxybutyl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-2-oxoethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-5-oxopentanoic acid?

The canonical SMILES for (4S)-4-[[(2S)-5-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-5-amino-2-[[(2S,3S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-amino-3-carboxypropanoyl]amino]-4-methylsulfanylbutanoyl]pyrrolidine-2-carbonyl]amino]-3-methylpentanoyl]amino]-5-oxopentanoyl]amino]propanoyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-5-oxopentanoyl]amino]-5-[(2S)-2-[[(2S)-1-[[(2S)-1-[[2-[(2S)-2-[[(2S)-1-[[(1S)-4-carbamimidamido-1-carboxybutyl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-2-oxoethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-5-oxopentanoic acid is [H]/N=C(\N)NCCC[C@H](NC(=O)[C@@H](NC(=O)[C@@H]1CCCN1C(=O)CNC(=O)[C@H](CC(C)C)NC(=O)[C@@H](NC(=O)[C@@H]1CCCN1C(=O)[C@H](CCC(=O)O)NC(=O)[C@H](CCC(N)=O)NC(=O)[C@H](Cc1ccc(O)cc1)NC(=O)[C@H](CC(C)C)NC(=O)[C@H](CC(C)C)NC(=O)[C@H](Cc1ccccc1)NC(=O)[C@H](C)NC(=O)[C@H](CCC(N)=O)NC(=O)[C@@H](NC(=O)[C@@H]1CCCN1C(=O)[C@H](CCSC)NC(=O)[C@@H](N)CC(=O)O)[C@@H](C)CC)C(C)C)C(C)C)C(=O)O.

What is the InChIKey of (4S)-4-[[(2S)-5-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-5-amino-2-[[(2S,3S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-amino-3-carboxypropanoyl]amino]-4-methylsulfanylbutanoyl]pyrrolidine-2-carbonyl]amino]-3-methylpentanoyl]amino]-5-oxopentanoyl]amino]propanoyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-5-oxopentanoyl]amino]-5-[(2S)-2-[[(2S)-1-[[(2S)-1-[[2-[(2S)-2-[[(2S)-1-[[(1S)-4-carbamimidamido-1-carboxybutyl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-2-oxoethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-5-oxopentanoic acid?

The InChIKey is VFGLVSFVDXLRBB-YDBUNGCJSA-N. The full InChI is InChI=1S/C102H160N24O27S/c1-15-57(12)83(123-95(146)75-28-22-43-126(75)100(151)66(39-44-154-14)113-85(136)62(103)50-80(133)134)98(149)112-63(33-36-76(104)128)87(138)110-58(13)84(135)116-71(48-59-23-17-16-18-24-59)92(143)118-69(46-53(4)5)89(140)117-70(47-54(6)7)90(141)119-72(49-60-29-31-61(127)32-30-60)91(142)111-64(34-37-77(105)129)88(139)114-65(35-38-79(131)132)99(150)125-42-21-27-74(125)94(145)122-82(56(10)11)97(148)120-68(45-52(2)3)86(137)109-51-78(130)124-41-20-26-73(124)93(144)121-81(55(8)9)96(147)115-67(101(152)153)25-19-40-108-102(106)107/h16-18,23-24,29-32,52-58,62-75,81-83,127H,15,19-22,25-28,33-51,103H2,1-14H3,(H2,104,128)(H2,105,129)(H,109,137)(H,110,138)(H,111,142)(H,112,149)(H,113,136)(H,114,139)(H,115,147)(H,116,135)(H,117,140)(H,118,143)(H,119,141)(H,120,148)(H,121,144)(H,122,145)(H,123,146)(H,131,132)(H,133,134)(H,152,153)(H4,106,107,108)/t57-,58-,62-,63-,64-,65-,66-,67-,68-,69-,70-,71-,72-,73-,74-,75-,81-,82-,83-/m0/s1.

What are the key properties of (4S)-4-[[(2S)-5-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-5-amino-2-[[(2S,3S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-amino-3-carboxypropanoyl]amino]-4-methylsulfanylbutanoyl]pyrrolidine-2-carbonyl]amino]-3-methylpentanoyl]amino]-5-oxopentanoyl]amino]propanoyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-5-oxopentanoyl]amino]-5-[(2S)-2-[[(2S)-1-[[(2S)-1-[[2-[(2S)-2-[[(2S)-1-[[(1S)-4-carbamimidamido-1-carboxybutyl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-2-oxoethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-5-oxopentanoic acid?

(4S)-4-[[(2S)-5-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-5-amino-2-[[(2S,3S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-amino-3-carboxypropanoyl]amino]-4-methylsulfanylbutanoyl]pyrrolidine-2-carbonyl]amino]-3-methylpentanoyl]amino]-5-oxopentanoyl]amino]propanoyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-5-oxopentanoyl]amino]-5-[(2S)-2-[[(2S)-1-[[(2S)-1-[[2-[(2S)-2-[[(2S)-1-[[(1S)-4-carbamimidamido-1-carboxybutyl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-2-oxoethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-5-oxopentanoic acid has a molecular weight of 2186.61 g/mol, XLogP of -3.13, 66 rotatable bonds, 25 hydrogen bond donors, and 27 hydrogen bond acceptors.

Where does this data come from?

All data for (4S)-4-[[(2S)-5-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-5-amino-2-[[(2S,3S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-amino-3-carboxypropanoyl]amino]-4-methylsulfanylbutanoyl]pyrrolidine-2-carbonyl]amino]-3-methylpentanoyl]amino]-5-oxopentanoyl]amino]propanoyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoyl]amino]-4-methylpentanoyl]amino]-3-(4-hydroxyphenyl)propanoyl]amino]-5-oxopentanoyl]amino]-5-[(2S)-2-[[(2S)-1-[[(2S)-1-[[2-[(2S)-2-[[(2S)-1-[[(1S)-4-carbamimidamido-1-carboxybutyl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-2-oxoethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]carbamoyl]pyrrolidin-1-yl]-5-oxopentanoic acid is sourced from PubChem (CID 177449429), the world's largest open chemistry database maintained by the National Library of Medicine (NIH).