Transcript Hot a-MSH Functions (From another poster)

HOT Functions of a-MSH Analogues
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Erectile Function
Feeding Behavior--Obesity
Pigmentation--Tanning
Reproductive Ability
Cardiovascular Function
Learning
Memory
Immune Response
Brief History of a-MSH Analogues
a-MSH
4
Uni versal acti ve, slight potent, with NO s electivity
7
[Nle , DPh e ]a-MSH
MT-I
Superpotent with NO se lectivity
Ac-Nle-Asp-His-DPh e-Arg-Trp-Lys-NH2
4
5
7
Superpotent with NO selectivity
10
[Nle , Asp , DPh e , Lys ]a-MSH4-10
MT-II
Ac-Nle-Asp-His-DNal(2')-Arg-Trp-Lys-NH2
4
5
7
10
[Nle ,Asp , DNal(2') , Lys ]a-MSH4-10
SHU9119
Ac-Nle-Asp-(1-Me)His-DNal(2')-Arg-Trp-Lys-NH2
4
5
6
7
10
[Nle , Asp , (1-Me)His , DNal(2') , Lys ]a-MSH4-10
WY012
Potent, MC1R and MC5R agonis ts
MC3R and MC4R antagonists
Potent, Se lective MC5 Antagonist
Synthesis of WY012 by SPPS
pMBHA Resin
Boc-AA
Fom
Pbf
Fmoc
Ac -Nle-Asp-(1-Me)His-DNal(2')-Arg-Trp-Lys pMBHA resin
For
1)
NH
2) HBTU/HOBt/DIEA
Pbf
Ac -Nle-Asp-(1-Me)His-DNal(2')-Arg-Trp-Lys pMBHA resin
HF Cleavage
Crude WY012
Purification
UGLY Facts related to Boc-(1-Me)His
• COST: US$645/g
• Synthesis
HCl.(1-Me)His
OH + NaOH
Hydrophilicity assessed by HPLC
(1’-Me)His and Boc-(1’-Me)His (Column
dead volume is around 3.2 minutes)
H2O/Dioxane
(1-Me)His O-Na+
NOTHING (Monitored by HPLC)
Boc2O
Boc-(1-Me)His
-
O Na
Organic Solvent Extraction
+
H+
Boc-(1-Me)His
OH
Proposed Tactics--Using DIEA Salts
Reason
Useful Alternative for protec ted AA
in Coupling stage
Required Starting Material
DIEA Used in Pe ptide Coupling
DIEA Salt of Protected Amino Acid
H-(1-Me)His-OH
NOT Commercially Av ailable
Inefficient Process
HCl. H-(1-Me)His-OH
Reality of the Synthesis of DIEA Salts
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HCl H-(1-Me)His-OH
~quant. DIEA/Boc2O
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Boc (1-Me)His DIEA + DIEA HCl
Mixture in Peptide Coupling ?
NO easy Separation
HPLC Analysis of Crude Peptides
a) From Boc-(1’-Me)His-OH; b) and c) From Boc-(1’-Me)-His DIEA and DIEA.HCl salts mix.
Column: Vydac C18; gradient: 10-90% A in 40 minutes [A: MeCN, B: (0.1%
TFA) H2O]; flow: 1.0 mL; detection: 230, 254, 280 nm.
Conclusions
• Mixture of Boc-(1’-Me)His.DIEA and DIEA.HCl salts
was Successfully Applied to Peptide Syntheses
• This Method has Various Advantages, Including: Very
Economic, Time-saving and Easy Access to
Starting Materials
• This Method Should be Applicable to Other
Hydrophilic Amino Acids
References and Acknowledgements
• 1. Eifler, S., Leblond, I., Trifilieff, E., and Lepoittevin, J.P., Letters Pept. Sci., 4(1997) 467.
• 2. Pennington, M.W., and Dunn, B.M., (Eds.), Peptide
Synthesis Protocols, Humana Press Inc., 1994.
• 3. Miyazawa, T., Otomatsu, T.; Yamada, T.; Kuwata, S.,
Chem. Express, 4(1989) 745.
Funded by Grants From US Public Health Service
Reprint: http://www.chem.arizona.edu/faculty/hrub/hruby.html
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