Oxidation of β-phenylethylamine by both types of monoamine oxidase: Effects of substrate concentration and PH

Сузукі, Осаму; Hattori, Hideki; Oya, Mototsugu; Katsumata, Yoshinao; Matsumoto, Takatoshi

doi:10.1016/0024-3205(79)90432-6

Cited by 25 publications

(7 citation statements)

References 12 publications

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“…This confirmed previous results in other species [28] and contrasted strongly with the characteristics of intestinal DAO, which was inhibited especially by histamine in concentrations > 10 -4 M [28]. In the rat brain, SuzuKI [29] demonstrated a strong substrate inhibition of MAO by PEA. But for the same organ and the same substrate KINEMUCHI [30] did not observe this effect up to concentrations of 1 raM.…”

Section: Properties Of Intestinal Maosupporting

confidence: 92%

“…It was, for instance, shown for PEA that this substrate was accessible for MAO types A and B [22,29]. Moreover, the characteristics of a MAO as a type A or B enzyme could vary with the incubation conditions (dependency on pH or substrate concentration) [29]. Another example of the lack of specificity was the finding that MAO types A and B from the beef heart both deaminated serotonin [27].…”

Section: The Role Of Mao In Histamine Catabolismmentioning

confidence: 97%

“…However, to use the substrate specificity for this purpose does not prove very helpful since it is not always typical of the one or the other type. It was, for instance, shown for PEA that this substrate was accessible for MAO types A and B [22,29]. Moreover, the characteristics of a MAO as a type A or B enzyme could vary with the incubation conditions (dependency on pH or substrate concentration) [29].…”

Section: The Role Of Mao In Histamine Catabolismmentioning

confidence: 99%

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Intestinal monoamine oxidase: Does it have a role in histamine catabolism?

1982

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The importance of intestinal diamine oxidase in histamine catabolism was proved in several series of experiments. However, intestinal monoamine oxidase might also be involved in histamine degradation either by direct deamination or by the deamination of methylated products. The soluble fraction of intestinal monoamine oxidase was purified and tested for the properties and substrate specificity by three different methods which are described in detail. Using 0.15 M phosphate buffer the optimum pH was 7.4--7.6. The Km values for serotonin and tyramine were 0.2 and 0.3 X 10(-3) M. The most favoured substrates of the enzyme were tyramine, tryptamine and serotonin, but it was not possible to classify the enzyme as a type A or B monoamine oxidase only by its substrate specificity. Histamine and ring methylated derivatives were not attacked by intestinal monoamine oxidase. This means that in the intestinal mucosa by the oxidative pathway of histamine is completely catalysed by diamine oxidase.

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Section: Properties Of Intestinal Maosupporting

confidence: 92%

Section: The Role Of Mao In Histamine Catabolismmentioning

confidence: 97%

Section: The Role Of Mao In Histamine Catabolismmentioning

confidence: 99%

See 1 more Smart Citation

Intestinal monoamine oxidase: Does it have a role in histamine catabolism?

1982

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“…Biphasic curves of the inhibition of PEA deamination by clorgyline were observed in rat vasa deferentia (Dial and Clark, 1978), lung (Kung and Wilson, 1979) and skeletal and cardiac muscles (Kwatra and Sourkes, 1979). In brain, clorgyline inhibited the deamination of PEA at pH 7.4 in a biphasic manner, this amine being about equally catabolised by both forms of MA0 when present at 100 p~ (Suzuki et al, 1979;Kinemuchi et al, 1980). Moreover, the double-reciprocal plots were nonlinear (inhibition by excess substrate) at amine concentrations above 40-50 p~.…”

Section: Discussionmentioning

confidence: 96%

Characteristics of the Inhibition of Rat Brain Monoamine Oxidase In Vitro by MD780515

Kan¹,

Benedetti²

1981

Journal of Neurochemistry

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The inhibiton of type A and B MAO in rat forebrain crude membrane preparation by MD780515, (3-(4-[(3-cyanophenyl)methoxy]phenyl)-5-(methoxymethyl)-2-oxazolidinone-Centre de Recherche Delalande, France) has been investigated in vitro with 5-hydroxytryptamine and beta-phenylethylamine as substrates. The inhibition of the high-affinity binding of [3H]harmaline, a specific marker of type A MAO, was also studied. In the experimental conditions used, MD780515 appeared to be a pure mixed MAO inhibitor (MAOI) of 5-HT deamination, both Km and Vmax being altered [Ki (Dixon) = Ki, (slope) = 2 nM; Ki (intercept) = 12 nM]. Phenylethylamine oxidation could be considered to be noncompetitively inhibited by MD780515 (Ki (slope) = 78 nM; Ki (intercept) = 103 nM). Dixon and intercept replots were hyperbolic, suggesting that, at high concentrations, PEA could be deaminated by both forms of MAO. This hypothesis was confirmed by biphasic inhibition curves of 80 microM-PEA obtained when MD780515, clorgyline, harmaline and deprenyl were used at MAOIs. MD780515 was a potent inhibitor (IC50 = 1-2 nM) of [3H]harmaline binding. Comparatively, clorgyline, 'cold' harmaline and Lilly 51641 inhibited 3H ligand binding, with IC50 of 5, 7 and 40 nM respectively. In conclusion, MD780515 is a reversible, specific and potent type A MAOI.

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“…It is generally known that (3-PEA oxidation is inhibited by high concentration of (3-PEA. Suzuki et al (40,41) and Kinemuchi et al (42) reported that the inhibition pattern by clorgyline or (-) deprenyl change markedly at different con centrations of (3-PEA and at different pH values and suggested that these changes are due to the strong substrate inhibition. These observations agree with this report which investigated monkey brain mitochondria using reaction media at pH 6.6 (optimum pH) and pH 7.2 for kinetic analysis.…”

Section: Discussionmentioning

confidence: 99%

Some interrelated properties of A and B form monoamine oxidase in monkey brain mitochondria.

1984

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Abstract-The multiplicity of monoamine oxidase (MAO) in monkey brain was studied by comparing the relationship between the selective substrates of MAO and the pH-activity curves obtained using these substrates.When mitochondrial and A-form MAO were used as the enzyme preparations with serotonin (5-HT) and norepinephrine (NE), preferential substrates for A-form MAO, the pH optima were 8.8 and 7.8 with 5-HT and 8.5 and 7.2 with NE. These substrates were also oxidized by B-form MAO after changing the pH of the incubation medium (shift to alkaline); these pH optima were 9.0 and 8.2, respectively.When common substrates of MAO were used (tyramine, octopamine, dopamine and tryptamine), the pH activity curves obtained were all broad and bell-shaped with pH optima for the 3 species of enzyme (mitochondria, A-form and B-form MAO) at 8.0, 7.8, and 8.0 with tyramine; 8.3, 7.5, and 8.5 with octopamine; 7.8, 7.5, and 8.5 with dopamine; and 8.0, 8.3, and 6.9 with tryptamine, respectively.The pH optima were 6.6 with (3 phenylethylamine (;3-PEA) and 9.0 with benzylamine, preferential substrates for B form MAO, for either mitochondria or B-form MAO. The Km values obtained for tryptamine and (3-PEA were lower than those for the other substrates of MAO, regardless of the enzyme preparations.The Km and Vmax values of both forms MAO for 5-HT and NE were similar to those of the A-form MAO. The differences in the Km and Vmah values of the A-form MAO and B-form MAO for common substrates were comparable.Tyramine, octopamine and dopamine were substrates for both forms MAO, with only a slight preference for B-form MAO over A-form MAO. However, tryptamine may be deaminated predominantly by A-form MAO.Monoamine oxidase [monoamine: oxygen oxidoreductase (deaminating), EC 1.4.3.4], commonly designated MAO, is responsible for metabolizing many endogenous mono amines, including serotonin (5-HT), norepin ephrine (NE), dopamine, octopamine, tyramine, tryptamine and (3-phenylethylamine (/3-PEA). A large number of xenobiotic compounds as well as endogenous mono amines are inhibitors of MAO; the elevation of mood by these compounds probably related to the accumulation of one or more of these amines.Recently, potent and selective irreversible inhibitors of MAO have been used to detect two forms of the enzyme in preparations from several sources (1, 2). A-form MAO is very sensitive to clorgyline (3), but B-form MAO is only inhibited by a high concen tration of clorgyline. In contrast, the drug (-)deprenyl (4) inhibits B-form MAO at a lower concentration than A-form MAO. 5-HT (3, 5) and NE (6) are preferential substrates for A-form MAO, and 8-PEA (7) and benzylamine (8) are preferential sub strates for B-form MAO. Dopamine (5), tyramine (7), tryptamine (1, 9) and octo pamine (10, 11) have been reported to be substrates in vitro for both forms of the enzyme. Although several workers (12-16) have attempted the separation of A and 13 form MAO, the nature of the two forms and the relationship between these forms are still obscure.Our previous studies (17,18...

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Oxidation of β-phenylethylamine by both types of monoamine oxidase: Effects of substrate concentration and PH

Cited by 25 publications

References 12 publications

Intestinal monoamine oxidase: Does it have a role in histamine catabolism?

Intestinal monoamine oxidase: Does it have a role in histamine catabolism?

Characteristics of the Inhibition of Rat Brain Monoamine Oxidase In Vitro by MD780515

Some interrelated properties of A and B form monoamine oxidase in monkey brain mitochondria.

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