Factors influencing pyrroline 5-carboxylate synthesis from glutamate by rat intestinal mucosa mitochondria

Journal Article · Sat Oct 15 04:00:00 EDT 1983 · Arch. Biochem. Biophys.; (United States)

DOI:https://doi.org/10.1016/0003-9861(83)90340-5· OSTI ID:5022491

Henslee, J G; Wakabayashi, Y; Small, C; Jones, M E

Factors influencing pyrroline 5-carboxylate (P5C) synthesis from glutamate by a subcellular fraction enriched in mitochondria of rat small intestinal mucosa have been studied. P5C synthesis decreased rapidly if this subcellular fraction was preincubated at 20 degrees C in the absence of substrates; this effect suggests that the enzyme(s) catalyzing P5C synthesis from glutamate (P5C synthase) is unstable in the absence of substrates. In the presence of substrates P5C synthesis increased linearly for the first 30 min of incubation, suggesting that the substrates promote enzyme stability. Pyridoxal 5'-phosphate is an effective inhibitor of P5C synthase whereas pyridoxamine 5'-phosphate and pyridoxal are not inhibitory. Potassium phosphate, KCl, and KBr each inhibited P5C synthase but potassium-Hepes (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) did not. Potassium phosphate was the most potent inhibitor followed by KBr, and then KCl. These results suggest P5C synthase is sensitive to anion inhibition. Both L-ornithine and D-ornithine inhibited P5C synthase; L-proline did not inhibit. Several analogs of ornithine and proline were also tested and none was found to inhibit P5C synthase; the inhibition by ornithine is, therefore, rather specific and it may prove to contribute to the regulation of metabolism of these amino acids.

• Research Organization: Univ. of North Carolina, Chapel Hill
• OSTI ID: 5022491
• Journal Information: Arch. Biochem. Biophys.; (United States), Journal Name: Arch. Biochem. Biophys.; (United States) Vol. 226:2; ISSN ABBIA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
AMINES
AMINO ACIDS
ANIMALS
AZOLES
BIOCHEMICAL REACTION KINETICS
BIOSYNTHESIS
BODY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
DIGESTIVE SYSTEM
ENZYME ACTIVITY
ENZYMES
GASTROINTESTINAL TRACT
GLUTAMIC ACID
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INHIBITION
INTESTINES
KINETICS
MAMMALS
MEMBRANES
METABOLISM
MITOCHONDRIA
MUCOUS MEMBRANES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANOIDS
ORGANS
ORNITHINE
OXIDOREDUCTASES
PROLINE
PYRROLES
PYRROLIDINES
RATS
REACTION KINETICS
RODENTS
SMALL INTESTINE
SYNTHESIS
VERTEBRATES