Pyrrolidonecarboxylic acid

Another serious problem is the tendency to select for sequencing immunoglobulin chains in which the amino terminus is unblocked because of the ability to use the sequencer. This too is skewing the data base so that answers to many questions cannot be obtained. Pyroglutamic acid (pyrrolidonecarboxylic acid) was present at the amino terminus in 18/21 human VHI, 5/6 VHH, and 5/5 VHIV chains sequenced as well as in 10/10 human VXI, 16/20 VxII, 3/3 V V, 19/19 mouse Vx chains and in the 1 pig Vx chain sequenced (Kabat et al., 1976b). 

Stable aqueous emulsions of poly(2-ethylhexyl acrylate) (PEHA) were also produced by RESAS from CO2 (68). In this case, a polymer suspension in CO2 was expanded instead of a dissolved solute. A C02-philic surfactant, Monasil PCA (PDMS-g-pyrrolidonecarboxylic acid), was utilized in dispersion polymerization to form a stable polymer suspension at 65°C and 345 bar. A hydrophilic surfactant, (e.g., SAM 185, Pluronic L61, or Pluronic L62), that is soluble in CO2 and CO2/2-EHA monomer mixtures as well as water was added to CO2 to stabilize the suspension after it had been rapidly expanded through a capillary into aqueous solution. The resulting aqueous emulsion with up to 15.6 wt % polymer content was stable for weeks with an average particle size of 2 to 3 pm. Another approach is to introduce the hydrophilic surfactant in the aqueous phase in addition to the surfactant in the CO2 phase. This approach is more general, since many hydrophilic surfactants are not soluble in CO2. During expansion of the suspension into an aqueous solution, the hydrophilic surfactant—for example, triblock Pluronic copolymers—dilfuses to the particle surface to provide stabilization. The resulting aqueous latexes were stable for 100 days for a polymer content reaching 12.7 wt %. 

Experiments (although subject to some criticism) carried out by Klein and Linser (57) would indicate that stachydrine formation in the plant is markedly increased by injection into the hollow stalks of the possible precursor of the betaine. On the assumption that stachydrine could result from simple methylation of proline which in turn might be derived from glutamic acid via pyrrolidonecarboxylic acid, or from arginine via ornithine, injections were made of 1-2 % solutions of proline, ornithine dihydrochloride and sodium glutamate. The experiments carried out on Stachys palustris L., Stachys recta L., and Galeopsis ochroleuca Lam. revealed an apparent increase in stachydrine content as a result of these injections. 

CAS 98-79-3 EINECS/ELINCS 202-700-3 Synonyms 5-Oxo-L-proline L-Pyroglutamic acid Pyrrolidonecarboxylic acid 2-Pyrrolidone-5-carboxylic acid Ciassification Cyclic organic compd. 

Pyrrolidone-2 a-Pyrrolidone. See2-Pyrrolidone Pyrrolidonecarboxylic acid 2-Pyrrolidone-5-carboxylic acid. See PCA Pyrrolldone, N-octyl-. See Caprylyl pyrrolidone Pyrrolo (3,4-c) pyrrole-1,4-dione, 3,6-bis (4-chlorophenyl)-2,5-dihydro. 

Chitosan, prod, with methyloxirane. See Hydroxypropyl chitosan Chitosan, pyrrolidonecarboxylic acid salt. See Chitosan PCA Chitosan succinamide Definition Monosuccinamide of chitosan Uses Film-former in cosmetics... 

Wilson, H., and R. K. Cannan The Glutamic acid-pyrrolidonecarboxylic acid system. J. Biol. Chem. 119, 309 (1937). 

A significant point of distinction is that in many mammalian species most X, but few k chains, are blocked at the N-terminus, i.e., have a terminal residue of pyrrolidonecarboxylic acid. Also, human and mouse k chains are distinguishable from X by the presence of a half-cystine residue at the C-terminal position of k chains in X chains the terminal sequence is -Cys-Ser. In each case, the cysteine residue forms a disulfide bond with the H chain. This feature cannot be generalized to all species since L chains of the chicken, which are of the X type according to sequence analysis (118), have a terminal half-cystine group (and an unblocked amino terminus) (118,119). Interestingly, the L chains of the... 

Wilson, H. and Cannan, R.K. (1937) The glutamic acid-pyrrolidonecarboxylic acid system. /. Biol Chem., 119, 309 - 331. 

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