Pseudomonas striata

Soil. Hydrolyzes in soil forming 3-chloroaniline (Bartha, 1971 Hartley and Kidd, 1987 Smith, 1988). In soil. Pseudomonas striata Chester, a Flavobacterium s >., an Agrobacterium s >., and an Achromobacter sp. readily degraded chlorpropham to 3-chloroaniline and 2-propanol. Subsequent degradation by enzymatic hydrolysis yielded carbon dioxide, chloride ions, and unidentified compounds (Kaufman, 1967). 

Figure 5. Proposed mechanism of CIPC cleavage by an enzyme isolated from pseudomonas striata Chester...

Source Arthrobacter crystallo- Arthrobacter aurescens Pseudomonas fluorescens Pseudomonas striata Pseudomonas sp. A)... 

An amino acid racemase which shows very broad substrate specificity was discovered in Pseudomonas striata (= Ps. putida), purified, and characterized1 91. The enzyme catalyzes racemization of various amino acids except aromatic and acidic... 

Hydantoinase/D-amino acida Pseudomonas striata J Ferm Technol 56 484(1978)... 

Pseudomonas striata, a Flavobacterium sp., an Agrobacterium sp. and an Achromobacterium sp. can live on propham and chlorpropham as their sole carbon source (Kaufmann and Kearney, 1965 Kaufmann and Blake, 1973). 

The hydantoinases are particularly useful enzymes because the hydan-toins are intermediates in the synthesis of many amino acids. Enzymes with specificities for the D- or the L-enantiomers are available. The enzyme from Pseudomonas striata is most active against dihydrouracil, and it is possible that this is its natural substrate. The most active substrates amongst the hydantoins are those formed from the neutral aliphatic amino acids, but several phenylglydne analogues are also hydrolysed. 

The bacterial D-hydantoinase has been isolated as crystals from cells of Pseudomonas putida (= P. striata) (Table 1) [5]. Because the purified enzyme showed the highest activity and affinity toward dihydrouracil, the enzyme was identified as dihydropyrimidinase (EC. 3.5.2.2). Interestingly, the enzyme also attacked a variety of aliphatic and aromatic D-5-mono-substituted hydantoins, yielding the corresponding D-form of N-carbamoyl-a-amino acids. Thus, the enzyme can be used for the preparation of various D-amino acids. Under the conditions used for the enzymatic hydrolysis of hydantoin at pH 8 to 10, the L-isomers of the remaining hydantoins are racemized through base catalysis. Therefore, the racemic hydantoins can be converted quantitatively into N-carbamoyl-D-amino acids through this step. 

Takahashi et al. [6] revealed that in Pseudomonas putida (= P. striata) BFO 12996 d-hydantoinase is identical with dihydropyrirnidinase (EC 3.5.2.2), which catalyzes the cyclic ureide-hydrolyzing step of the reductive degradation of pyrimidine bases (Fig. 4). The same results were obtained for other hydantoinases from Pseudomonas sp. [22,23], Com-amonas sp. [23], Bacillus sp. [9], Arthrobacter sp. [24], Agrobacterium sp. [22], and rat liver [25]. From these results, it is proposed that D-amino acid production from dl-5-monosubstituted hydantoins involves the action of the series of enzymes involved in the pyrimidine degradation pathway [24,26,27], However, this contenticm has remained moot because of a lack of systematic studies on the enzymes involved in these transformations [28]. 

D-Hydantoinase was isolated from mammalian cells as well as from bacteria. The bovine liver enzyme is identical to dihydrop3nimidmase and consists of four subunits [31]. It was reported to have four Zn which are tightly bound sirnilar to that of rat dihydropyiimi-dinase [32]. Bacterial D-hydantoinase was isolated from various sources such as P. putida (= P. striata) IFO 12996 [6], Pseudomonas sp. AJ 11220 [27], Pseudomonas fluorescens DSM 84 [33], Bacillus stearothermophilus SDl [34], Blastobacter sp. A17p-4 [35], and Arthrobacter crystallopoietes AM2 [24]. The substrate specificities of some D-hydanto-inases are summarized in Table 3. It can be seen that all bacterial D-hydantoinases other than the enzyme from Agrobacterium sp. IP 1-671 [30] are rather similar to file mammalian dihydropyrimidinase. D-Hydantoinase from Agrobacterium sp. IP 1-671 is specific for D-5-monosubstituted hydantoin and has no dihydropyrimidinase activity. All bacterial d-hydantoinases other than the thermostable enzyme from B. stearothermophilus are homo-tetramer with molecular masses of 190-260 kDa. The enzyme from B. stearothermophilus is homodimer with a molecular mass of 126 kDa. These enzymes activities require divalent cations such as Mg, Mn, Fe, Co, or Zn for their expression of maximum activity. 

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