Purification et detection de plusieurs formes moleculaires de l'histidine decarboxylase de la muqueuse gastrique de rat

Savany, A; Cronenberger, L

doi:10.1016/0005-2744(78)90309-1

Cited by 9 publications

(7 citation statements)

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“…This indicates that the brain enzyme is slightly different from fetal enzyme. The presence of multiple forms of histidine decarboxylase in the stomach is essentially consistent with the report of SAVANY and CRONENBERGER [38,53], although they reported the presence of three forms of histidine decarboxylase from rat stomach and their pI values are slightly different from ours. 5), confirming previous findings [34] that in Ouchterlony's double diffusion test, the precipitin line of anti-fetal-enzyme antiserum against the fetal enzyme fused with the precipitin line against the brain enzyme with spur formation.…”

Section: Discussionsupporting

confidence: 92%

Comparison of histidine decarboxylases from rat stomach and brain with that from whole bodies of rat fetus

et al. 1984

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Histidine decarboxylases from the stomach and brain of adult rats were purified 380- and 160-fold, respectively, and their properties compared with those of the enzyme from whole bodies of fetal rats (7600-fold purification). The molecular weights (about 90,000) and the apparent Km values for L-histidine (3 X 10(-4) M) of the three enzymes were similar. The pI value of the fetal enzyme was 5.0, and that of the brain enzyme was 5.4. Histidine decarboxylase of the stomach showed two peaks of activity corresponding to those of the fetal and brain enzymes (pI's of 5.0 and 5.4) on isoelectric focusing. Anti-fetal-histidine decarboxylase antiserum inhibited the stomach and fetal enzymes extensively, but the brain enzyme only slightly. These results indicate that there are at least two types of histidine decarboxylase in rat tissue.

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Section: Discussionsupporting

confidence: 92%

Comparison of histidine decarboxylases from rat stomach and brain with that from whole bodies of rat fetus

et al. 1984

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“…4) and suggest the presence of several enzymatic forms of the purified enzyme. These multiple forms are distinguished by structural properties [14], which here seem to affect their heat stability, perhaps through coenzyme binding. The biphasic curves observed are consistent with two enzymatic forms: one thermolabile corresponding to 50% of the total activity, the other more stable; in fact, although biphasic curves were observed, this second form is complex because the heat denaturation curves at 55 "C, 57 "C and 60 "C are parallel while residual activities are different.…”

Section: Discussionmentioning

confidence: 99%

“…The purification procedure was the same as previously described [14]. The final enzyme extract in 50 mM phosphate buffer pH 6.8, containing 10 pM pyridoxal phosphate, was concentrated to about 5 ml by ultrafiltration.…”

Section: Histidine Decarboxylase Purificationmentioning

confidence: 99%

“…Histidine decarboxylase activity was assayed by measuring I4CO2 released from ~~-Icarhoxyl-'~C]histidine as previously described [14]. The standard assay mixture contained in a total volume of 1.2 ml: 50 mM potassium phosphate buffer pH 6.8, 20 pM pyridoxal phosphate, enzyme; after a 5-min preincubation at 37 "C the reaction was started by addition of substrate (50 pM L-histidine, 0.1 pCi DL-[cffi"bo~~.l-'"C]-histidine).…”

Section: Enzyme Assaymentioning

confidence: 99%

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Properties of Histidine Decarboxylase from Rat Gastric Mucosa

Savany

Cronenberger

1982

European Journal of Biochemistry

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The properties of specific histidine decarboxylase from highly purified rat gastric mucosa preparations were studied. The kinetic parameters were pH dependent: the apparent K, value varied inversely with pH; the maximum reaction velocity was reached at pH 6.6; the optimum pH was related to substrate concentration. The enzyme was unstable below pH 5.5. The effect of temperature was investigated and the enzyme activity was optimum near 56°C. The thermal inactivation of the enzyme showed the presence of several active forms displaying distinct thermostabilities. The effect of coenzyme and substrate on heat stability was established. A small amount of pyridoxal phosphate was required for maximum enzyme activity, and the K, was low. The cofactor appeared to be tightly bound to the apoenzyme; nevertheless there was a fraction more easily resolved by dialysis. With high pyridoxal phosphate concentrations non-competitive inhibition occurred. Histamine inhibited the enzyme at high concentrations, the inhibition being competitive with respect to the substrate. No metal ion was required for enzyme activity; the enzyme was inhibited by sulfhydryl reagents and heavy metal ions, and also by high concentrations of reducing agents. The tryptophan residue of the holoenzyme seemed to be essential for the catalytic process.Histamine, which has an important role in a variety of physiological and pathological responses [I], is synthesised through the decarboxylation of histidine. In mammalian tissues the synthesis can be catalyzed by an enzyme which has a high specificity for histidine and is different from the nonspecific aromatic-L-amino acid decarboxylase. This specific histidine decarboxylase is found in many tissues but its activity is generally low; however, fetal rat tissue, hamster placenta and mastocytomas have high activities [2 -51. A high histamine-forming capacity has also been found in the gastric mucosa of several mammalian species including man [6-111. Studies concerning the histidine decarboxylases isolated from different sources allowed us to establish that they were similar in many respects [12]. However, the gastric enzyme studies have been principally performed on crude or partially purified preparations. The fact that rat gastric mucosa, which is rich in specific histidine decarboxylase, also contains a high activity of the non-specific enzyme [6] results in a difficult and false characterization of the specific enzyme.The properties of gastric histidine decarboxylase can be studied with accuracy only after the enzyme has been purified. Attempts to purify the specific gastric enzyme have been limited by the enzyme lability upon fractionation [9,13]. However, in a previous study [I41 we reported that a high degree of purification of the specific histidine decarboxylase from rat gastric mucosa had been obtained; only the specific enzyme was obtained by that procedure, the non-specific enzyme was absent. Its physicochemical properties were investigated, the enzyme consists of three active forms, the stability and ...

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“…We previously obtained the specific gastric histidine decarboxylase with a high specific activity (Savany & Cronenberger, 1978); the enzyme consists of several forms that can be distinguished by analytical thin-layer isoelectric focusing on polyacrylamide gel, as they have characteristic isoelectric points. A large number of enzymes are found to exist as multiple molecular forms; several forms of other mammalian decarboxylases, e.g.…”

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confidence: 99%

Isolation and properties of multiple forms of histidine decarboxylase from rat gastric mucosa

Savany¹,

Cronenberger²

1982

Biochemical Journal

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The heterogeneity of histidine decarboxylase from rat gastric mucosa was studied. The partially purified enzyme was fractionated by preparative isoelectric focusing on a flat-gel bed by using narrow pH-range carrier ampholytes and a short focusing time. The activity was resolved, with about 95% recovery, into three forms, designated I, II and III, with pI values of 5.90, 5.60 and 5.35 respectively. These three forms exhibited similar molecular weights, indicating that the forms were not the result of different degrees of polymerization. By preparative refocusing each form refocused as a single peak of enzyme activity with reproducible pI, but a high loss of activity occurred with repeated focusing. Forms I, II and III were purified by the combined use of preparative isoelectric focusing and gel chromatography and other fractionation methods. The active forms could be distinguished by electrophoresis and isoelectric focusing on polyacrylamide gels and displayed protein heterogeneity. These forms were found in the crude extract and in the partially purified preparations in the presence or absence of proteinase inhibitors. Form II had the highest specific activity, but all three forms had the same optimum pH and Km value for histidine.

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Purification et detection de plusieurs formes moleculaires de l'histidine decarboxylase de la muqueuse gastrique de rat

Cited by 9 publications

References 31 publications

Comparison of histidine decarboxylases from rat stomach and brain with that from whole bodies of rat fetus

Comparison of histidine decarboxylases from rat stomach and brain with that from whole bodies of rat fetus

Properties of Histidine Decarboxylase from Rat Gastric Mucosa

Isolation and properties of multiple forms of histidine decarboxylase from rat gastric mucosa

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