Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P80404 (GABA transaminase)
 786 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two forms of GABA transaminase which could be distinguished by ion-exchange chromatography have been separated and purified in pig brain. The two forms have different Km values for alpha-ketoglutarate and show different degrees of inhibition by various salts. Although the two forms are separable, they have identical antigenic properties, pH optima, and NH2 terminal amino acid composition, and they appear to be of the same molecular size. The biological significance or the relationship between multiple forms of GABA transaminase is not yet understood.
 ...
PMID:Two forms of GABA transaminase in pig brain: purification and properties. 616 12

The activity of certain key enzymes involved in glutamic acid metabolism was studied in purified brain mitochondria and in mitochondrial subfractions separated in a discontinuous 1.2--1.6 mol/l sucrose gradient. Alanine aminotransferase and glutamate dehydrogenase were found to be matrix enzymes and aspartate aminotransferase to be associated with the inner mitochondrial membranes. After the purified mitochondria had been separated into 5 subfractions, aspartate aminotransferase and NAD+-dependent isocitrate dehydrogenase were found to be bound to the lighter mitochondrial subfractions settling at the 1.4--1.5 mol/l sucrose boundary while alanine aminotransferase, 4-aminobutyrate transaminase and glutamate dehydrogenase were associated with the heavier subfractions settling below 2.4 mol/l sucrose. The highest specific activity of the given enzymes was found in the subfraction settling at the 1.4--1.5 mol/l sucrose boundary, the only exception being alanine aminotransferase activity, whose maximum was found in the subfractions settling in 1.5 and 1.6 mol/l sucrose. It was concluded that alanine aminotransferase, in conjunction with glutamate dehydrogenase, is linked to NH3 binding and to the oxidation of reduced adenine nucleotides; in addition, alanine aminotransferase is presumed to have the function of transporting glutamate from the mitochondria to the extramitochondrial space.
 ...
PMID:Alanine aminotransferase and some other enzymes in different populations of free brain cortex mitochondria. 645 52

The aldehyde produced from the oxidative deamination of primary and secondary amines by the monoamine oxidases (EC 1.4.3.4; MAO) or the semicarbazide-sensitive amine oxidases (EC 1.4.3.6; SSAO) may be determined followed reaction at elevated temperatures with 2-diphenylacetyl-1,3-indandione-1-hydrazone (DIH), separation by high-performance chromatography liquid (C-8 column, eluting isocratically with acetonitrile, ammonium acetate, water) and fluorimetric detection (excitation and emission wavelengths 430 and 525 nm). The detection limits for benzaldehyde, p-hydroxybenzaldehyde and 2-phenylacetaldehyde were 125 nM, 150 and 62.3 nM, respectively. Thus the assay is appropriate for determination of amine oxidase activities towards benzylamine, 2-phenylethylamine and tyramine. The fluorescence of the DIH adduct with indole-3-aldehyde was strongly quenched, giving a relatively high detection limit (17.5 microM). The detection limit was lower (3.8 microM) when the absorbance at 430 nm was monitored. Enzyme activities determined by this procedure were shown to be linear with enzyme-protein concentration (rat liver mitochondria). The presence of 1-2 mM semicarbazide, necessary for determining MAO activities in samples also containing SSAO, did not adversely affect the derivatization reaction. The DIH-aldehyde adducts were sufficiently stable to permit their storage at low temperatures prior to assay. The product produced by reaction of 5-hydroxyindole acetaldehyde with DIH had no significant fluorescence and too low an absorbance at 430 nm to allow its determination for assay of activities towards 5-HT. This procedure can also measure succinic semialdehyde (detection limit 240 nM) and thus would be applicable to the determination of GABA transaminase activity.
 ...
PMID:Determination of monoamine oxidase activity by HPLC with fluorimetric detection. 1059 Oct 46