(4S)-5-[[(2S)-6-amino-1-[[(2S)-1-[[(2S)-5-amino-1-[[(2S,3R)-1-[(2S)-2-[[(2S)-1-[[(2S)-1-[[(2S,3R)-1-[[(2S)-1-[[(1S)-1-carboxy-2-phenylethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-hydroxy-1-oxobutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]carbamoyl]pyrrolidin-1-yl]-3-hydroxy-1-oxobutan-2-yl]amino]-1,5-dioxopentan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-1-oxohexan-2-yl]amino]-4-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]amino]propanoyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylsulfanylbutanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxypropanoyl]amino]-5-oxopentanoic acid

C93H142N20O28S — CID 22806256

About (4S)-5-[[(2S)-6-amino-1-[[(2S)-1-[[(2S)-5-amino-1-[[(2S,3R)-1-[(2S)-2-[[(2S)-1-[[(2S)-1-[[(2S,3R)-1-[[(2S)-1-[[(1S)-1-carboxy-2-phenylethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-hydroxy-1-oxobutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]carbamoyl]pyrrolidin-1-yl]-3-hydroxy-1-oxobutan-2-yl]amino]-1,5-dioxopentan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-1-oxohexan-2-yl]amino]-4-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]amino]propanoyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylsulfanylbutanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxypropanoyl]amino]-5-oxopentanoic acid

(4S)-5-[[(2S)-6-amino-1-[[(2S)-1-[[(2S)-5-amino-1-[[(2S,3R)-1-[(2S)-2-[[(2S)-1-[[(2S)-1-[[(2S,3R)-1-[[(2S)-1-[[(1S)-1-carboxy-2-phenylethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-hydroxy-1-oxobutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]carbamoyl]pyrrolidin-1-yl]-3-hydroxy-1-oxobutan-2-yl]amino]-1,5-dioxopentan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-1-oxohexan-2-yl]amino]-4-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]amino]propanoyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylsulfanylbutanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxypropanoyl]amino]-5-oxopentanoic acid (PubChem CID 22806256) has the molecular formula C93H142N20O28S and a molecular weight of 2020.34 g/mol. Its IUPAC name is (4S)-5-[[(2S)-6-amino-1-[[(2S)-1-[[(2S)-5-amino-1-[[(2S,3R)-1-[(2S)-2-[[(2S)-1-[[(2S)-1-[[(2S,3R)-1-[[(2S)-1-[[(1S)-1-carboxy-2-phenylethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-hydroxy-1-oxobutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]carbamoyl]pyrrolidin-1-yl]-3-hydroxy-1-oxobutan-2-yl]amino]-1,5-dioxopentan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-1-oxohexan-2-yl]amino]-4-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]amino]propanoyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylsulfanylbutanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxypropanoyl]amino]-5-oxopentanoic acid.

Molecular Properties

• Compound Name: (4S)-5-[[(2S)-6-amino-1-[[(2S)-1-[[(2S)-5-amino-1-[[(2S,3R)-1-[(2S)-2-[[(2S)-1-[[(2S)-1-[[(2S,3R)-1-[[(2S)-1-[[(1S)-1-carboxy-2-phenylethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-hydroxy-1-oxobutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]carbamoyl]pyrrolidin-1-yl]-3-hydroxy-1-oxobutan-2-yl]amino]-1,5-dioxopentan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-1-oxohexan-2-yl]amino]-4-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]amino]propanoyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylsulfanylbutanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxypropanoyl]amino]-5-oxopentanoic acid
• PubChem CID: 22806256
• Molecular Formula: C93H142N20O28S
• Molecular Weight: 2020.34 g/mol
• Exact Mass: 2019.00
• IUPAC Name: (4S)-5-[[(2S)-6-amino-1-[[(2S)-1-[[(2S)-5-amino-1-[[(2S,3R)-1-[(2S)-2-[[(2S)-1-[[(2S)-1-[[(2S,3R)-1-[[(2S)-1-[[(1S)-1-carboxy-2-phenylethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-hydroxy-1-oxobutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]carbamoyl]pyrrolidin-1-yl]-3-hydroxy-1-oxobutan-2-yl]amino]-1,5-dioxopentan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-1-oxohexan-2-yl]amino]-4-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]amino]propanoyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylsulfanylbutanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxypropanoyl]amino]-5-oxopentanoic acid
• SMILES: CSCC[C@H](NC(=O)[C@H](Cc1ccccc1)NC(=O)CNC(=O)[C@@H](C)NC(=O)[C@@H](N)Cc1ccc(O)cc1)C(=O)N[C@H](C(=O)N[C@@H](CO)C(=O)N[C@@H](CCC(=O)O)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CO)C(=O)N[C@@H](CCC(N)=O)C(=O)N[C@H](C(=O)N1CCC[C@H]1C(=O)N[C@@H](CC(C)C)C(=O)N[C@H](C(=O)N[C@H](C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](Cc1ccccc1)C(=O)O)[C@@H](C)O)C(C)C)[C@@H](C)O)[C@@H](C)O
• InChI: InChI=1S/C93H142N20O28S/c1-47(2)39-63(83(130)106-66(93(140)141)43-55-23-16-13-17-24-55)105-90(137)75(52(9)117)111-89(136)73(49(5)6)109-85(132)64(40-48(3)4)104-88(135)69-26-20-37-113(69)92(139)76(53(10)118)112-81(128)60(31-33-70(96)120)101-86(133)67(45-114)107-79(126)59(25-18-19-36-94)100-80(127)61(32-34-72(122)123)102-87(134)68(46-115)108-91(138)74(51(8)116)110-82(129)62(35-38-142-11)103-84(131)65(42-54-21-14-12-15-22-54)99-71(121)44-97-77(124)50(7)98-78(125)58(95)41-56-27-29-57(119)30-28-56/h12-17,21-24,27-30,47-53,58-69,73-76,114-119H,18-20,25-26,31-46,94-95H2,1-11H3,(H2,96,120)(H,97,124)(H,98,125)(H,99,121)(H,100,127)(H,101,133)(H,102,134)(H,103,131)(H,104,135)(H,105,137)(H,106,130)(H,107,126)(H,108,138)(H,109,132)(H,110,129)(H,111,136)(H,112,128)(H,122,123)(H,140,141)/t50-,51-,52-,53-,58+,59+,60+,61+,62+,63+,64+,65+,66+,67+,68+,69+,73+,74+,75+,76+/m1/s1
• InChIKey: CDWYWLQXCIPSOU-RUHSQIJESA-N
• XLogP: -6.88
• TPSA: 777.02 Ų
• H-Bond Donors: 27
• H-Bond Acceptors: 29
• Rotatable Bonds: 63
• Heavy Atoms: 142
• Complexity: —

Lipinski Rule of Five

3 violations

Rule	Value
MW ≤ 500	2020.34
LogP ≤ 5	-6.88
H-Bond Donors ≤ 5	27
H-Bond Acceptors ≤ 10	29

Computed Properties (RDKit)

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

Frequently Asked Questions

What is the IUPAC name of (4S)-5-[[(2S)-6-amino-1-[[(2S)-1-[[(2S)-5-amino-1-[[(2S,3R)-1-[(2S)-2-[[(2S)-1-[[(2S)-1-[[(2S,3R)-1-[[(2S)-1-[[(1S)-1-carboxy-2-phenylethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-hydroxy-1-oxobutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]carbamoyl]pyrrolidin-1-yl]-3-hydroxy-1-oxobutan-2-yl]amino]-1,5-dioxopentan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-1-oxohexan-2-yl]amino]-4-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]amino]propanoyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylsulfanylbutanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxypropanoyl]amino]-5-oxopentanoic acid?

The IUPAC name of (4S)-5-[[(2S)-6-amino-1-[[(2S)-1-[[(2S)-5-amino-1-[[(2S,3R)-1-[(2S)-2-[[(2S)-1-[[(2S)-1-[[(2S,3R)-1-[[(2S)-1-[[(1S)-1-carboxy-2-phenylethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-hydroxy-1-oxobutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]carbamoyl]pyrrolidin-1-yl]-3-hydroxy-1-oxobutan-2-yl]amino]-1,5-dioxopentan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-1-oxohexan-2-yl]amino]-4-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]amino]propanoyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylsulfanylbutanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxypropanoyl]amino]-5-oxopentanoic acid (CID 22806256) is (4S)-5-[[(2S)-6-amino-1-[[(2S)-1-[[(2S)-5-amino-1-[[(2S,3R)-1-[(2S)-2-[[(2S)-1-[[(2S)-1-[[(2S,3R)-1-[[(2S)-1-[[(1S)-1-carboxy-2-phenylethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-hydroxy-1-oxobutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]carbamoyl]pyrrolidin-1-yl]-3-hydroxy-1-oxobutan-2-yl]amino]-1,5-dioxopentan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-1-oxohexan-2-yl]amino]-4-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]amino]propanoyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylsulfanylbutanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxypropanoyl]amino]-5-oxopentanoic acid.

What is the SMILES notation for (4S)-5-[[(2S)-6-amino-1-[[(2S)-1-[[(2S)-5-amino-1-[[(2S,3R)-1-[(2S)-2-[[(2S)-1-[[(2S)-1-[[(2S,3R)-1-[[(2S)-1-[[(1S)-1-carboxy-2-phenylethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-hydroxy-1-oxobutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]carbamoyl]pyrrolidin-1-yl]-3-hydroxy-1-oxobutan-2-yl]amino]-1,5-dioxopentan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-1-oxohexan-2-yl]amino]-4-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]amino]propanoyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylsulfanylbutanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxypropanoyl]amino]-5-oxopentanoic acid?

The canonical SMILES for (4S)-5-[[(2S)-6-amino-1-[[(2S)-1-[[(2S)-5-amino-1-[[(2S,3R)-1-[(2S)-2-[[(2S)-1-[[(2S)-1-[[(2S,3R)-1-[[(2S)-1-[[(1S)-1-carboxy-2-phenylethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-hydroxy-1-oxobutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]carbamoyl]pyrrolidin-1-yl]-3-hydroxy-1-oxobutan-2-yl]amino]-1,5-dioxopentan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-1-oxohexan-2-yl]amino]-4-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]amino]propanoyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylsulfanylbutanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxypropanoyl]amino]-5-oxopentanoic acid is CSCC[C@H](NC(=O)[C@H](Cc1ccccc1)NC(=O)CNC(=O)[C@@H](C)NC(=O)[C@@H](N)Cc1ccc(O)cc1)C(=O)N[C@H](C(=O)N[C@@H](CO)C(=O)N[C@@H](CCC(=O)O)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CO)C(=O)N[C@@H](CCC(N)=O)C(=O)N[C@H](C(=O)N1CCC[C@H]1C(=O)N[C@@H](CC(C)C)C(=O)N[C@H](C(=O)N[C@H](C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](Cc1ccccc1)C(=O)O)[C@@H](C)O)C(C)C)[C@@H](C)O)[C@@H](C)O.

What is the InChIKey of (4S)-5-[[(2S)-6-amino-1-[[(2S)-1-[[(2S)-5-amino-1-[[(2S,3R)-1-[(2S)-2-[[(2S)-1-[[(2S)-1-[[(2S,3R)-1-[[(2S)-1-[[(1S)-1-carboxy-2-phenylethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-hydroxy-1-oxobutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]carbamoyl]pyrrolidin-1-yl]-3-hydroxy-1-oxobutan-2-yl]amino]-1,5-dioxopentan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-1-oxohexan-2-yl]amino]-4-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]amino]propanoyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylsulfanylbutanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxypropanoyl]amino]-5-oxopentanoic acid?

The InChIKey is CDWYWLQXCIPSOU-RUHSQIJESA-N. The full InChI is InChI=1S/C93H142N20O28S/c1-47(2)39-63(83(130)106-66(93(140)141)43-55-23-16-13-17-24-55)105-90(137)75(52(9)117)111-89(136)73(49(5)6)109-85(132)64(40-48(3)4)104-88(135)69-26-20-37-113(69)92(139)76(53(10)118)112-81(128)60(31-33-70(96)120)101-86(133)67(45-114)107-79(126)59(25-18-19-36-94)100-80(127)61(32-34-72(122)123)102-87(134)68(46-115)108-91(138)74(51(8)116)110-82(129)62(35-38-142-11)103-84(131)65(42-54-21-14-12-15-22-54)99-71(121)44-97-77(124)50(7)98-78(125)58(95)41-56-27-29-57(119)30-28-56/h12-17,21-24,27-30,47-53,58-69,73-76,114-119H,18-20,25-26,31-46,94-95H2,1-11H3,(H2,96,120)(H,97,124)(H,98,125)(H,99,121)(H,100,127)(H,101,133)(H,102,134)(H,103,131)(H,104,135)(H,105,137)(H,106,130)(H,107,126)(H,108,138)(H,109,132)(H,110,129)(H,111,136)(H,112,128)(H,122,123)(H,140,141)/t50-,51-,52-,53-,58+,59+,60+,61+,62+,63+,64+,65+,66+,67+,68+,69+,73+,74+,75+,76+/m1/s1.

What are the key properties of (4S)-5-[[(2S)-6-amino-1-[[(2S)-1-[[(2S)-5-amino-1-[[(2S,3R)-1-[(2S)-2-[[(2S)-1-[[(2S)-1-[[(2S,3R)-1-[[(2S)-1-[[(1S)-1-carboxy-2-phenylethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-hydroxy-1-oxobutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]carbamoyl]pyrrolidin-1-yl]-3-hydroxy-1-oxobutan-2-yl]amino]-1,5-dioxopentan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-1-oxohexan-2-yl]amino]-4-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]amino]propanoyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylsulfanylbutanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxypropanoyl]amino]-5-oxopentanoic acid?

(4S)-5-[[(2S)-6-amino-1-[[(2S)-1-[[(2S)-5-amino-1-[[(2S,3R)-1-[(2S)-2-[[(2S)-1-[[(2S)-1-[[(2S,3R)-1-[[(2S)-1-[[(1S)-1-carboxy-2-phenylethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-hydroxy-1-oxobutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]carbamoyl]pyrrolidin-1-yl]-3-hydroxy-1-oxobutan-2-yl]amino]-1,5-dioxopentan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-1-oxohexan-2-yl]amino]-4-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]amino]propanoyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylsulfanylbutanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxypropanoyl]amino]-5-oxopentanoic acid has a molecular weight of 2020.34 g/mol, XLogP of -6.88, 63 rotatable bonds, 27 hydrogen bond donors, and 29 hydrogen bond acceptors.

Where does this data come from?

All data for (4S)-5-[[(2S)-6-amino-1-[[(2S)-1-[[(2S)-5-amino-1-[[(2S,3R)-1-[(2S)-2-[[(2S)-1-[[(2S)-1-[[(2S,3R)-1-[[(2S)-1-[[(1S)-1-carboxy-2-phenylethyl]amino]-4-methyl-1-oxopentan-2-yl]amino]-3-hydroxy-1-oxobutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-4-methyl-1-oxopentan-2-yl]carbamoyl]pyrrolidin-1-yl]-3-hydroxy-1-oxobutan-2-yl]amino]-1,5-dioxopentan-2-yl]amino]-3-hydroxy-1-oxopropan-2-yl]amino]-1-oxohexan-2-yl]amino]-4-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]amino]propanoyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylsulfanylbutanoyl]amino]-3-hydroxybutanoyl]amino]-3-hydroxypropanoyl]amino]-5-oxopentanoic acid is sourced from PubChem (CID 22806256), the world's largest open chemistry database maintained by the National Library of Medicine (NIH).