Three types of stereospecificity and the kinetic deuterium isotope effect in the oxidative deamination of dopamine as catalyzed by different amine oxidases

1988 ◽  
Vol 66 (8) ◽  
pp. 853-861 ◽  
Author(s):  
Peter H. Yu
Keyword(s):  
Isotope Effect ◽  
Amine Oxidase ◽  
Deuterium Atom ◽  
Amine Oxidases ◽  
Deuterium Isotope Effect ◽  
Plasma Amine Oxidase ◽  
Benzylamine Oxidase ◽  
Rate Limiting ◽  
Hog Kidney ◽  
Pea Seedling

When the stereospecifically deuterated dopamine enantiomers, (R)- and (S)-[α-2H1]dopamine, are incubated with amine oxidases, the deuterium atom may be either retained to form monodeuterated 3,4-dihydroxyphenylacetaldehyde, or eliminated to produce the nondeuterated or protio-aldehyde product. These two aldehydes can be separated from one another and identified by high-performance liquid chromatography with electrochemical detection. Three types of stereospecific abstraction of a hydrogen from the α-carbon of dopamine during deamination have been observed. In the first type, the pro-R hydrogen is removed from the α-carbon. Enzymes in this category are mitochondrial monoamine oxidases A and B, as isolated from different tissues and species. The second type of deamination involves the abstraction of pro-S hydrogen from the α-carbon of dopamine. Soluble enzymes, such as rat aorta benzylamine oxidase or diamine oxidase from hog kidney and pea seedling, have been found to belong to this group. Bovine plasma amine oxidase exhibits the third type of deamination where no absolute stereospecificity is required. This enzyme catalyzes the oxidation of either (S)- or (R)-[α-2H1]dopamine, preferably breaking the C—H bond rather than the C—2H bond in both cases. The kinetic deuterium isotope effect during the deamination of dopamine catalyzed by the different amine oxidases varies greatly; VH/VD ranges from 1.5 to 5.5. The high magnitude of the isotope effect suggests that hydrogen abstraction may be the rate-limiting step (i.e., in reactions catalyzed by benzylamine oxidase and monoamine oxidase). When the isotope effect is low (i.e., for diamine oxidases from hog kidney or pea seedling), it is uncertain if the breaking of the bond is rate limiting.

scholarly journals The amine oxidases of human placenta and pregnancy plasma

1974 ◽  
Vol 139 (1) ◽  
pp. 169-181 ◽  
Author(s):  
William G. Bardsley ◽  
M. James C. Crabbe ◽  
Ian V. Scott
Keyword(s):  
Diamine Oxidase ◽  
Amine Oxidase ◽  
Enzyme System ◽  
Placental Tissue ◽  
Amine Oxidases ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Ping Pong ◽  
Normal Human ◽  
Rate Limiting

1. The purification of monoamine oxidase and diamine oxidase from normal human term placental tissue is described. 2. The properties of these enzymes are reported and compared with the properties of unpurified human pregnancy plasma. 3. This comparison shows that the amine oxidase of pregnancy plasma has properties corresponding to purified placental diamine oxidase, suggesting a placental origin for the plasma enzyme system. 4. Detailed kinetic study of the purified placental diamine oxidase suggests that it has a Ping Pong sequence, a mechanism of action and rate-limiting step similar to the diamine oxidase of pig kidney. 5. It is suggested that the enzyme system is important in protecting the foeto-placental unit from excesses of biogenic amines.

scholarly journals The organic cofactor in plasma amine oxidase: evidence for pyrroloquinoline quinone and against pyridoxal phosphate

1987 ◽  
Vol 241 (2) ◽  
pp. 603-608 ◽  
Author(s):  
P F Knowles ◽  
K B Pandeya ◽  
F X Rius ◽  
C M Spencer ◽  
R S Moog ◽  
...  
Keyword(s):  
Pyridoxal Phosphate ◽  
Amine Oxidase ◽  
Resonance Raman ◽  
Pyrroloquinoline Quinone ◽  
Spectral Studies ◽  
Amine Oxidases ◽  
Plasma Enzymes ◽  
Bovine Plasma ◽  
Plasma Amine Oxidase ◽  
Derivatives Of

Plasma amine oxidases (EC 1.4.3.6) are classified as containing the organic cofactor pyridoxal phosphate. Biochemical and bioassays on the pig plasma amine oxidase fail to reveal the presence of pyridoxal phosphate and 31P n.m.r. evidence is also inconsistent with pyridoxal phosphate in the enzyme. Resonance Raman spectral studies on phenylhydrazone derivatives of the pig and bovine plasma enzymes have been carried out and comparisons made with the corresponding derivatives of pyridoxal phosphate and pyrroloquinoline quinone (PQQ). The resonance Raman evidence indicates that the cofactor in both plasma amine oxidases is PQQ or a closely related species and not pyridoxal phosphate. The results substantiate earlier reports concerning the identity of the organic cofactor.

scholarly journals Studies on the active site of pig plasma amine oxidase

1989 ◽  
Vol 264 (3) ◽  
pp. 663-669 ◽  
Author(s):  
D Collison ◽  
P F Knowles ◽  
F E Mabbs ◽  
F X Rius ◽  
I Singh ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Site ◽  
Oxidase Activity ◽  
Amine Oxidase ◽  
Spectral Characteristics ◽  
Pyrroloquinoline Quinone ◽  
Amine Oxidases ◽  
Assay Procedure ◽  
Plasma Amine Oxidase ◽  
Amine Oxidase Activity

Amine oxidase from pig plasma (PPAO) has two bound Cu2+ ions and at least one pyrroloquinoline quinone (PQQ) moiety as cofactors. It is shown that recovery of activity by copper-depleted PPAO is linear with respect to added Cu2+ ions. Recovery of e.s.r. and optical spectral characteristics of active-site copper parallel the recovery of catalytic activity. These results are consistent with both Cu2+ ions contributing to catalysis. Further e.s.r. studies indicate that the two copper sites in PPAO, unlike those in amine oxidases from other sources, are chemically distinct. These comparative studies establish that non-identity of the Cu2+ ions in PPAO is not a requirement for amine oxidase activity. It is shown through the use of a new assay procedure that there are two molecules of PQQ bound per molecule of protein in PPAO; only the more reactive of these PQQ moieties is required for activity.

Spermine oxidase and benzylamine oxidase. Distribution, development and substrate specificity

1962 ◽  
Vol 156 (963) ◽  
pp. 268-279 ◽  
Keyword(s):  
Blood Plasma ◽  
Amine Oxidase ◽  
Enzymic Activity ◽  
Secondary Amines ◽  
Spermine Oxidase ◽  
Amine Oxidases ◽  
Newborn Piglets ◽  
Wood Shavings ◽  
Mammalian Blood ◽  
Benzylamine Oxidase

A survey has been made of the distribution of the two types of amine oxidase that occur in mammalian blood plasma. Spermine oxidase has been found in all ruminants (Ruminantia and Tylopoda) examined, and also in the hippopotamus and two members of the order Hyracoidea. Benzylamine oxidase has a much wider distribution; it occurs not only in Ungulates and Carnivores, but has also been found in some Primates. Benzylamine oxidase was not found in the blood plasma of newborn piglets; in newborn foals the enzymic activity was low. Spermine oxidase activity, absent or very low in the newborn kid, developed at similar rates in kids kept with the mother, bedded on straw, and in those removed from the mother and bedded on wood shavings. The plasma amine oxidases differ from the intracellular amine oxidase in that they are unable to oxidize N -methylated secondary amines.

scholarly journals Microbial oxidation of amines. Distribution, purification and properties of two primary-amine oxidases from the yeast Candida boidinii grown on amines as sole nitrogen source

1981 ◽  
Vol 199 (1) ◽  
pp. 187-201 ◽  
Author(s):  
Geoffrey W. Haywood ◽  
Peter J. Large
Keyword(s):  
Amino Acids ◽  
Amine Oxidase ◽  
Primary Amines ◽  
Carbon Chain Length ◽  
Candida Boidinii ◽  
Amine Oxidases ◽  
Microbial Oxidation ◽  
Ph Optimum ◽  
Benzylamine Oxidase ◽  
As If

1. The yeast Candida boidinii was grown on glucose as carbon source with a range of amines and amino acids as nitrogen sources. Cells grown on amines contained elevated activities of catalase. If the amines contained N-methyl groups, formaldehyde dehydrogenase, formate dehydrogenase and S-formylglutathione hydrolase were also elevated in activity compared with cells grown on (NH4)2SO4. 2. Cells grown on all the amines tested, but not those grown on urea or amino acids, contained an oxidase attacking primary amines, which is referred to as methylamine oxidase. In addition, cells grown on some amines contained a second amine oxidase, which is referred to as benzylamine oxidase. 3. Both amine oxidases were purified to near homogeneity. 4. Benzylamine oxidase was considerably more stable at 45 and 50°C than was methylamine oxidase. 5. Both enzymes had a pH optimum in the region of 7.0, and had a considerable number of substrates in common. There were, however, significant differences in the substrate specificity of the two enzymes. The ratio V/Kapp.m increased with increasing n-alkyl carbon chain length for benzylamine oxidase, but decreased for methylamine oxidase. 6. Both enzymes showed similar sensitivity to carbonyl-group reagents, copper-chelating agents and other typical ‘diamine oxidase inhibitors’. 7. The stoicheiometry for the reaction catalysed by each enzyme was established. 8. The kinetics of methylamine oxidase were examined by varying the methylamine and oxygen concentrations in turn. A non-Ping Pong kinetic pattern with intersecting double-reciprocal plots was obtained, giving Km values of 10mum for O2 and 198mum for methylamine. The significance of this unusual kinetic behaviour is discussed. Similar experiments were not possible with the benzylamine oxidase, because it seemed to have an even lower Km for O2. 9. Both enzymes had similar subunit Mr values of about 80000, but the benzylamine oxidase behaved as if it were usually a dimer, Mr 136000, which under certain conditions aggregated to a tetramer, Mr 288000. Methylamine oxidase was mainly in the form of an octamer, Mr 510000, which gave rise quite readily to dimers of Mr 150000, and on gel filtration behaved as if the Mr was 286000.

Enzymic aromatization of deuterium labelled testosterone and androst-4-ene-3,17-dione

1981 ◽  
Vol 59 (19) ◽  
pp. 2809-2819 ◽  
Author(s):  
Herbert L. Holland ◽  
Gregg J. Taylor
Keyword(s):  
Double Bond ◽  
Isotope Effect ◽  
Nmr Spectra ◽  
Deuterium Nmr ◽  
Secondary Effects ◽  
Deuterium Isotope Effect ◽  
Oxidative Removal ◽  
Primary And Secondary Effects ◽  
Rate Limiting

The preparation and aromatization by human placental microsomes of androst-4-ene-3-ones labelled with deuterium at C-4, C-6α, C-6β, C-16, and C-19 is described. Deuterium nmr spectra are reported for these compounds and for a sample of a 1,2-dideuterated androst-4-ene-3-one; the latter is formed nonstereospecifically by reduction of the C-1(2) double bond of a Δ1,4-diene-3-one. Aromatization by placental microsomes occurs with retention of deuterium at C-4 and C-6, but with some loss from C-16. The aromatization of 19-d1 and 19,19,19-d3 steroids in the presence of 16,16-d2 steroids has been carried out to determine the deuterium isotope effect for the oxidative removal of C-19. The values obtained (kH/kD for 19-d1 = 2.3, kH/kD for 19,19, 19-d3 = 3.2) are a combination of primary and secondary effects, but suggest that oxidation at C-19 is a rate-limiting reaction of the biosynthetic sequence.The fungus Pellicularia filamentosa NRRL 2727, reported to hydroxylate androst-4-ene-3,17-dione at C-19, gave only the products of hydroxylation at C-11α, C-11β, and C-14.

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