Amine oxidases reaction scheme

Scheme 35 shows the multistep synthesis of optically pure tritium-labeled histamine, which involves an amine oxidase-catalyzed reaction as the first step [250], Diamine oxidase (DAMOX) from pea seedlings catalyze the oxidative deamination of diamines. DAMOX-catalyzed reactions of diamines in the synthesis of phenacyl azaheterocycles is shown in Scheme 36 [251-255],... 

Scheme 5 The reductive half-reaction of TPQ-dependent amine oxidases.

An interesting aspect of the elucidation of the structure and mechanisms of TPQ biogenesis and function is that for these amine oxidases certain amino acid residues have multiple roles during cofactor biogenesis and catalysis. This is clearly true for the tyrosine residue, which is converted into TPQ, It has also been demonstrated by site-directed mutagenesis that a second strictly conserved tyrosine residue, which is present in the active site is also required for TPQ biogenesis and influences catalysis. Furthermore, the bound copper serves dual functions in cofactor biosynthesis, as shown in Scheme 4 as well as during catalysis. The latter function appears to be in stabilization of transient intermediates in the oxidative half reaction. ... 

Hordeam (Bailey).—Smith has isolated from barley shoots a particulate fraction which contains an amine-oxidase. This enzyme converts spermine (48) into 1,3-diaminopropane and l-(3-aminopropyl)-A -pyrroline (S3). The spermine is presumably dehydrogenated, affording the Schiff base (SOX which on hydrolysis yields 13-diaminopropane and the amino-aldehyde (SI). Cyclization of this compound yields the methanolamine (S2) and thence the pyrrolinc by dehydration (Scheme 11). Spermidine (49) yields A -pyrroline (S4) and 1,3-diaminopropane by a similar series of reactions. This amine-oxidase was also found in oats Avena sativa), maizefZen mays), wheat (Triticum vulgare), and rye (Secale cereale). 

Simplified reaction scheme for the oxidation of an amine to the corresponding imine through FAD-containing amine oxidases (AOs). 

The reaction scheme for the deracemization of (substituted) 1-phenylethyl amine derivatives by the combination of a monoamine oxidase (MAO) with an co-TA ATA (amino transferase) denotes the commercially available co-TAs from Codexis. 

In the above described carbonylation reactions the nucleophile that reacts with the species released from the catalytic cycle is water or possibly an alcohol. This can be replaced by a more nucleophilic amine, yielding an amide as the product [66]. With this minor variation a different group of products becomes accessible. A striking application of this reaction is the synthesis of the monoamine oxidase B inhibitor Lazabemide [70, 75]. The first laboratory synthesis could be shortened from 8 steps to just one catalytic reaction with a TON of 3000 (Scheme 5.41). The only drawback to the greenness of this reaction is that the metal is removed via an extraction with aqueous NaCN. 

Fig. 2.18 Simplified scheme of the cycle/aUocation of magnesium in a green plant. Mg is involved - inter aha - in making peptide bonds, in tricarboxylate cycle, hydrolysis of molecules and binding of CO (ribulose-bisphosphatecarboxylase/oxidase or PEP carboxylase in plants which also employs Mg or Mtf+ in some plants (Kai et al. 2003)). Reaction steps in which Mg takes part as biocatalyst are marked by broken lines/arrows. Citrate and other intermediates of the tricarboxylate cycle, particularly malate, are employed by higher plants for extraction of essential metals, including Mg, Fe and Mn (thus the closed loop) from soil via and by means of the roots. This closed loop depicts a manner of autocatalysis. Amino acids which are required for protein biosynthesis are produced by reductive amination from tricarboxylate cycle intermediates and other 2-oxoadds which likewise eventually...

Guanidine derivatives of tetrahydroisoquinoline are generally prepared by the route shown in Scheme 5.21. The von Braun reaction converts the secondary amine (84) into the cyanamide (85) and hydrogen sulphide addition in pyridine-triethylamine gives the thiourea (86). Alkylation with bromoethane and treatment with ammonia complete the preparation of debrisoquin (87) and guanisoquin (88) [95], Recently, direct reaction of (85) with anhydrous ammonia to give (87) has been achieved [96]. The two guanidines are antihypertensives of which debrisoquin is the more useful. It appears to act in part by inhibition of neuronal monoamine oxidases [97]. 

Albumins. — [ HjRaffinose (76) has been treated with D-galactose oxidase and then coupled to albumin by reductive amination (Scheme 15). The reaction provides a convenient method of labelling albumin for studies of the organ sites of catabolism of proteins in the circulation. 

Scheme 5.19 Asymmetric oxidase aerobic coupling reactions utilizing copper-amine complexes, (a) Ligand = (+)-PMP,...

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