Abstract |
alpha-Guanidinoglutaric acid (alpha-GGA) has been reported to occur in the cerebral cortex after epileptic seizures. No physical characteristics of alpha-GGA have been given. A practical procedure for the preparation of alpha-GGA is reported here. alpha-GGA forms a lactam in aqueous solution at 80 degrees C. It is proposed to substitute this lactam, 1-amidino-2-pyrrolidone-5-carboxylic acid ( pAGlu), for pyroglutamic acid (pGlu) at the N-terminal position in neuropeptides to modify their biological characteristics. L(+)-Glutamic acid was reacted with S-methylisothiourea (I) at pH 10 in aqueous solution to form L(-)- alpha-guanidinoglutaric acid: mp 165-168 degrees C, [alpha]22D = -22.7 (C = 4, 2 M HCl). alpha-GGA reacted promptly with excess reagent to form a salt, S-methylisothiourea-alpha-guanidinoglutarate: mp 209-210 degrees C, [alpha]22D = -13.0 (C = 4, 2 M HCl). I was removed from the salt with aqueous picric acid, since I readily formed an insoluble picrate, S-methylisothiourea picrate (mp 225-228 degrees C). Alternatively, the salt was added to a cation exchange column, and the alpha-GGA was eluted with molar ammonium acetate buffer, pH 9.5. Its lactam, 1-amidino-2-pyrrolidone-5-carboxylic acid, mp 248-249 degrees C, [alpha]22D = +2.1 (C = 4, 2 M HCl), formed a picrate (mp 196-199 degrees C).
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Authors | S Natelson |
Journal | Analytical biochemistry
(Anal Biochem)
Vol. 156
Issue 1
Pg. 31-7
(Jul 1986)
ISSN: 0003-2697 [Print] United States |
PMID | 2874749
(Publication Type: Journal Article)
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Chemical References |
- Glutamates
- Glutarates
- Picrates
- Pyrrolidinones
- 1-amidino-2-pyrrolidone-5-carboxylic acid
- Isothiuronium
- Glutamic Acid
- alpha-guanidinoglutaric acid
- picric acid
- S-methylisothiopseudouronium
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Topics |
- Chemical Phenomena
- Chemistry
- Glutamates
- Glutamic Acid
- Glutarates
(chemical synthesis)
- Isothiuronium
(analogs & derivatives)
- Magnetic Resonance Spectroscopy
- Optical Rotation
- Picrates
- Pyrrolidinones
(chemical synthesis)
- Spectrophotometry, Infrared
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