Enzymatic Conversion Of D-Glutamic Acid to D-Pyrrolidone Carboxylic Acid by Mammalian Tissues

Nature ◽  
1962 ◽  
Vol 194 (4828) ◽  
pp. 557-559 ◽  
Author(s):  
ALTON MEISTER ◽  
MARTHA W. BUKENBERGER
Keyword(s):  
Carboxylic Acid ◽  
Glutamic Acid ◽  
Enzymatic Conversion ◽  
Mammalian Tissues ◽  
Pyrrolidone Carboxylic Acid

The metabolism of L-proline by jack pine seedlings

1971 ◽  
Vol 49 (12) ◽  
pp. 2163-2173 ◽  
Author(s):  
D. J. Durzan ◽  
P. K. Ramaiah
Keyword(s):  
Amino Acids ◽  
Carboxylic Acid ◽  
Glutamic Acid ◽  
Specific Activity ◽  
Jack Pine ◽  
Sharp Drop ◽  
Peroxidase Isoenzyme ◽  
Succinamic Acid ◽  
Pine Seedlings ◽  
Pyrrolidone Carboxylic Acid

The metabolism of L-proline was studied in 6-day-old jack pine seedlings, freshly excised from the nutritive female gametophyte. During the following 24 h, a sharp drop in free amino acids and protein was observed. Although levels of free proline were low, uniformly labeled 14C-L-proline and proline-3, 4-3H served as precursors for the dicarboxylic amino acids and their corresponding amides, glutamine and asparagine, which usually accumulate during germination. The origin of asparagine while unresolved did not involve β-cyanoalanine. Other products of proline metabolism included Δ1-pyrroline-5-carboxylic acid, glutamic acid, and γ-aminobutyric acid. With 14C-proline, radioactivity in alanine and serine resulted presumably from refixation of 14CO2 that was released by the decarboxylation of glutamic acid and other organic acids. The remaining products, e.g. pyrrolidone carboxylic acid, succinamic acid, and succinimide, were more closely related to the fate of glutamine than to proline.Radioactivity in proline and derived amino acids was recovered from soluble proteins separated on polyacrylamide gels. Five fractions revealed a similar diurnal turnover of specific activity. Three of these contained peroxidase isoenzyme activity. The recovery of tritium from peroxidase isoenzymes was related through the metabolism of proline to the intake and metabolism of water as well as to the appearance of enzyme activity in vascular tissues and emerging root and shoot apices.

Nitrogen metabolism of Picea glauca. V. Metabolism of uniformly labeled 14C-L-proline and 14C-L-glutamine by dormant buds in late fall

1973 ◽  
Vol 51 (2) ◽  
pp. 359-369 ◽  
Author(s):  
D. J. Durzan
Keyword(s):  
Carboxylic Acid ◽  
Glutamic Acid ◽  
Picea Glauca ◽  
Glutamine Metabolism ◽  
Aminobutyric Acid ◽  
Common Path ◽  
Carbon 14 ◽  
Keto Acids ◽  
Early Fall ◽  
Pyrrolidone Carboxylic Acid

In early fall, the high levels of free arginine nitrogen in spruce buds were eventually replaced by proline nitrogen, and in late spring, glutamine nitrogen accumulated. In late October when levels of free proline nitrogen were high, bud primordia from terminal shoots were excised and exposed to uniformly labeled 14C-L-proline and 14C-L-glutamine. The main early products from 14C-L-proline were Δ1-pyrroline-5-carboxylic acid, glutamic-γ-semialdehyde, and glutamic acid. Later products included glutamine, γ-aminobutyric acid, and to a much lesser extent pyrrolidone carboxylic acid, ornithine, and arginine. In protein, radioactivity was recovered from proline, glutamic acid, and hydroxyproline.Products from 14C-glutamine were mainly glutamic and α-ketoglutaric acid as well as proline, γ-aminobutyric acid, alanine, and pyrrolidone carboxylic acid. In protein, glutamic acid, aspartic acid, and proline contained carbon-14. Results indicated that proline and glutamine were related by their carbon metabolism through a common path involving glutamic acid. However, the main feature of glutamine metabolism was the removal of its α-amino and the amide nitrogen to yield α-keto acids especially α-ketoglutaric acid. The occurrence of α-ketoglutaramic acid could have accounted for succinamic acid and succinimide derived from 14C-L-glutamine.

scholarly journals N-(5′-Phosphopyridoxyl)glutamic acid and N-(5′-phosphopyridoxyl)-2-oxopyrrolidine-5-carboxylic acid and their action on the apoenzyme of aspartate aminotransferase

1971 ◽  
Vol 124 (1) ◽  
pp. 99-106 ◽  
Author(s):  
R M. Khomutov ◽  
H B. F. Dixon ◽  
L V. Vdovina ◽  
M P. Kirpichnikov ◽  
Y V. Morozov ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Glutamic Acid ◽  
Aspartate Aminotransferase ◽  
Fluorescence Spectra ◽  
Pyridoxal Phosphate ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Compound I ◽  
Compound Ii

1. N-(5′-Phosphopyridoxyl)-l-glutamic acid (P-Pxy-Glu, compound I) is readily converted at pH3 into a substance (P-Pxy-Glp, compound II) characterized as N-(5′-phosphopyridoxyl)-2-oxopyrrolidine-5-carboxylic acid. 2. The u.v., i.r. and fluorescence spectra of P-Pxy-Glu and P-Pxy-Glp have been determined; from the u.v. spectra their pK values have been found and compared. 3. The apoenzyme of aspartate aminotransferase is rapidly and irreversibly inactivated by P-Pxy-Glu, but is inactivated more slowly by P-Pxy-Glp. The complex with P-Pxy-Glp is stable enough to be isolated, but it is slowly reactivated in the presence of excess of pyridoxal phosphate. 4. The u.v. spectrum of the complex of apoenzyme and P-Pxy-Glp suggests that it contains a hydrogen bond between the phenolic hydroxyl group and the pyrrolidone nitrogen; this specifies the conformation of most of the molecule of P-Pxy-Glp. This conformation is similar to that previously postulated for the enzyme–glutamate complex except for the side chain of glutamate. Hence both the affinity of P-Pxy-Glp for the apoenzyme and the fact that it is more easily removed than P-Pxy-Glu are explicable.

Enzymic Formation of Pyrrolidone Carboxylic Acid from γ-Glutamyl Peptides

Nature ◽  
1956 ◽  
Vol 177 (4504) ◽  
pp. 377-378 ◽  
Author(s):  
GEORGE E. CONNELL ◽  
CHARLES S. HANES
Keyword(s):  
Carboxylic Acid ◽  
Pyrrolidone Carboxylic Acid
Sign in / Sign up

Export Citation Format

Share Document