Summary
Transamination between γ-aminobutyrate and α-ketoglutarate provides a pathway for the utilization of γ-aminobutyrate in fruit-bodies of Agaricus bisporus Lge. This reaction leads to the formation of succinic semialdehyde, a metabolic intermediate in the metabolism of γ-aminobutyrate to succinate in the cell. γ-aminobutyrate: α-ketoglutarate aminotransferase (E.C. 2.6.1.19) was sonically extracted from the mitochondrial fraction and partially purified by DEAE-cellulose column chromatography. Aminotransferase had a pH optimum between 8.1 and 8.5 and did not require pyridoxal-phosphate in vitro; however, the enzyme was inhibited by carbonyl-trapping reagents such as pyridoxal-phosphate activated enzymes. The Km values for γ-aminobutyrate and α-ketoglutarate calculated from Lineweaver-Burk plots were 2.2×10-4 M and 2.5×10-3 M, respectively. The transaminase was specific for α-ketoglutarate but not for γ-aminobutyrate; aspartate, α-alanine and δ-aminovalerianate also functioned as amino-group donors. Activity of the enzyme was not influenced by the addition of carboxylic acids of the Krebs cycle. The reversal of the transamination reaction showed optimal rates at pH 9.0–9.3. Some considerations on the physiological significance of these results are given.
Similar content being viewed by others
Abbreviations
- DEAE:
-
diéthylaminoéthyl
- EDTA:
-
éthylène diamine tétraacétate
- DCIP:
-
2,6-dichlorophénol-indophénol
- GABA:
-
acide γ-aminobutyrique
- GABA-T:
-
γ-aminobutyrate: α-cétoglutarate aminotransférase
- GAD:
-
L-glutamate décarboxylase
- Glu:
-
acide glutamique
- α-KG:
-
α-cétoglutarate
- MBTH:
-
3-méthyl-2-benzothiazolinone hydrazone
- PLP:
-
pyridoxal-5′-phosphate
- PMS:
-
phénazine méthosulfate
- SSA:
-
acide semialdéhyde succinique
- TCA:
-
acide trichloracétique
- Tris:
-
2-amino-2-(hydroxyméthyl)-1,3-propanediol
Références
Baldy, P., Latché, J.C.: Etude du métabolisme de l'acide γ-aminobutyrique dans les carpophores d'Agaricus bisporus Lge: incorporation d'acide γ-aminobutyrique 1-14C. C.R. Acad. Sci. (Paris) Sér. D. 275, 2123–2126 (1972)
Baldy, P.: Métabolisme de l'acide γ-aminobutyrique dans les carpophores d'Agaricus bisporus Lge. Etude préliminaire de la γ-aminobutyrate: α-cétoglutarate aminotransférase et de la semialdéhyde succinate: NAD(P) oxydoréductase. C.R. Acad. Sci. (Paris) Sér. D. 275, 2877–2880 (1972)
Baldy, P.: Métabolisme du γ-aminobutyrate chez Agaricus bisporus. I. La L-glutamate-1-carboxy-lyase. Physiol. Plant. 34, 365–372 (1975)
Baldy, P., Latché, J.C.: Quelques aspects de la biosynthèse et de l'utilisation de l'acide γ-aminobutyrique, possible source d'azote pour Agaricus bisporus Lge. Mushroom Science. IX (sous presse)
Bloch-Tardy, M., Rolland, B., Gonnard, P.: Pig brain 4-aminobutyrate 2-Keto glutarate transaminase. Purification, kinetics and physical properties. Biochimie 56, 823–832 (1974)
Bruce, R., Sims, K., Pitts, Jr., F.N.: Synthesis and purification of succinic semialdehyde. Analyt. Biochem. 41, 271–273 (1971)
Dixon, R.O.D., Fowden, L.: γ-aminobutyric acid metabolism in plants. Part 2. Metabolism in higher plants. Ann. Bot. 25, 513–530 (1961)
Forest, J.C., Wightman, F.: Amino acid metabolism in plants. III. Purification and some properties of a multispecific aminotransferase isolated from bushbean seedlings (Phaseolus vulgaris L.). Canad. J. Biochem. 50, 813–829 (1972)
Gadal, P.: Sur le métabolisme du chêne et de ses zoocécidies. Etude particulière de la biosynthèse des acides aminés aromatiques. Thèse Doct. Sci. Nat. Toulouse (1970)
Gallinet, J.P.: Les mitochondries des champignons supérieurs: composition de la chaîne respiratoire des mitochondries d'Agaricus campestris (F.) var. bisporus. C.R. Acad Sci. (Paris) Sér. D. 277, 2693–2696 (1973)
Hall, Z.W., Kravitz, E.A.: The metabolism of γ-aminobutyric acid (GABA) in the lobster nervous system. I. GABA-glutamate transaminase. J. Neurochem. 14, 45–54 (1967)
Kammeraat, C., Veldstra, H.: Characterization of succinate semialdehyde dehydrogenase from rat brain. Biochim. Biophys. Acta 151, 1–10 (1968)
King, T.E.: Reconstitution of respiratory enzyme systems. XI. Use of artificial electron acceptors in the assay of succinate-dehydrogenating enzymes. J. Biol. Chem. 238, 4032–4036 (1963)
Lang, C.A.: Simple microdetermination of Kjeldahl nitrogen in biological materials. Analyt. Chem. 30, 1692–1694 (1958)
Latché, J.C.: Quelques aspects du métabolisme azoté du carpophore d'Agaricus bisporus Lge. Etude en fonction du phénomène des volées. Thèse Doct. Sci. Nat. Toulouse (1970)
O'Leary, M.H.: Coenzyme analog inhibitors of apoglutamate decarboxylase. Biochem. 8, 1117–1122 (1969)
Lowry, O.H.: Rosebrough, N.J., Farr, A.L., Randall, R.J.: Protein measurement with the Folin phenol reagent. J. biol. Chem. 193, 265–275 (1951)
Paz, M.A., Blumenfeld, O.O., Rojkind, M., Henson, E., Furfine, C., Gallop, P.M.: Determination of carbonyl compounds with N-methyl benzothiazolone Hydrazone. Arch. Biochem. Biophys. 109, 548–559 (1965)
Piquemal, M.: Sur le métabolisme de l'acide glutamique source d'azote et de carbone pour le mycelium d'Agaricus bisporus. Thèse Doct. Spécialité (Physiologie Végétale), Toulouse (1970)
Prescott, B.A., Waelsch, H.: A microdetermination of glutamic acid and its application to protein analysis. J. biol. Chem. 164, 331–343 (1946)
Sanchez-Medina, F., Mayor, F.: L-glutamate-1-carboxy-lyase and 4-aminobutyrate: 2-oxoglutarate aminotransferase in succulent plants. Rev. esp. Fisiol. 26, 217–224 (1970)
Sawicki, E., Hauser, T.R., Stanley, T.W., Elbert, W.: The 3-methyl-2-benzothiazolone hydrazone test. Sensitive new methods for the detection, rapid estimation, and determination of aliphatic aldehydes. Analyt. Chem. 33, 93–96 (1961)
Scott, F.M., Jakoby, W.B.: Soluble γ-aminobutyric-glutamic transaminase from Pseudomonas fluorescens. J. biol. Chem. 234, 932–936 (1959)
Streeter, J.G., Thompson, J.F.: In vivo and in vitro studies on γ-aminobutyric metabolism with the radish plant (Raphanus sativus L.). Plant. Physiol. 49, 579–584 (1972)
Sytinsky, I.A., Vasilijev, V.Y.: Some catalytic properties of purified γ-aminobutyrate-α-oxoglutarate transaminase from the rat brain. Enzymologia 39, 1–11 (1970)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Baldy, P. Metabolisme du γ-aminobutyrate chez Agaricus bisporus Lge.. Planta 130, 275–281 (1976). https://doi.org/10.1007/BF00387833
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00387833