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1.
The ability of Aspergillus fumigatus
l-amino acid oxidase (l-aao) to cause the resolution of racemic mixtures of dl-amino acids was investigated with dl-alanine, dl-phenylalanine, dl-tyrosine, and dl-aspartic acid. A chiral column, Crownpak CR+ was used for the analysis of the amino acids. The enzyme was able to cause the
resolution of the three dl-amino acids resulting in the production of optically pure d-alanine (100% resolution), d-phenylalanine (80.2%), and d-tyrosine (84.1%), respectively. The optically pure d-amino acids have many uses and thus can be exploited industrially. This is the first report of the use of A. fumigatus
l-amino acid oxidase for racemic resolution of dl-amino acids. 相似文献
2.
Eco-Efficiency Analysis of biotechnological processes 总被引:1,自引:0,他引:1
Saling P 《Applied microbiology and biotechnology》2005,69(1):1-8
For almost 50 years now, biotechnological production processes have been used for industrial production of amino acids. Market development has been particularly dynamic for the flavor-enhancer glutamate and the animal feed amino acids l-lysine, l-threonine, and l-tryptophan, which are produced by fermentation processes using high-performance strains of Corynebacterium glutamicum and Escherichia coli from sugar sources such as molasses, sucrose, or glucose. But the market for amino acids in synthesis is also becoming increasingly important, with annual growth rates of 5–7%. The use of enzymes and whole cell biocatalysts has proven particularly valuable in production of both proteinogenic and nonproteinogenic l-amino acids, d-amino acids, and enantiomerically pure amino acid derivatives, which are of great interest as building blocks for active ingredients that are applied as pharmaceuticals, cosmetics, and agricultural products. Nutrition and health will continue to be the driving forces for exploiting the potential of microorganisms, and possibly also of suitable plants, to arrive at even more efficient processes for amino acid production. 相似文献
3.
T. Ohshiro M. Shinji Y. Morita Y. Takayama Y. Izumi 《Applied microbiology and biotechnology》1997,48(4):546-548
Microorganisms capable of cleaving the urethane bond of t-butoxycarbonyl (Boc) amino acids in a whole-cell reaction were screened among stock cultures, and Corynebacterium aquaticum IFO12154 was the most promising. The conversion of Boc-Ala to Ala was stimulated by CoSO4 in the medium and reaction mixture. The optimum whole-cell concentration was 25 mg lyophilized cells/ml. Boc-l-Met was the best substrate for this reaction, and other Boc-L-amino acids, as well as benzyloxycarbonyl-l-amino acids with hydrophobic residues, were also good substrates. Boc-d- and Z-d-amino acids were inert. When the reactions had proceeded for 24 h with each substrate at 10 mM, the molar conversion rates
from Boc-l-, dl- and d-Met were 100%, 50%, and 0% respectively. From 150 mM Boc-l-Met, 143 mM l-Met was formed at a molar yield of 95.3%.
Received: 3 September 1996 / Received last revision: 7 April 1997 / Accepted: 19 April 1997 相似文献
4.
Utilization of d-amino acids being substrates of d-amino acid dehydrogenase of Salmonella typhimurium was examined. The experiments were done with wild type strains and the mutants dadA missing the enzyme activity and dadR in which its synthesis is released from catabolite repression. Growth on d-tryptophan, d-histidine and d-methionine used as precursors of the l-amino acids was faster when the respective auxotrophs carried dadR mutations. The dadR mutants grew faster when d-or l-alanine was present as a sole source of nitrogen. Experiments with d-amino acid dehydrogenase in vitro provided evidence that d-tryptophan is its substrate with a very low affinity to the dehydrogenase. 相似文献
5.
Byung-Kwan Cho Joo-Hyun Seo Juhan Kim Chang-Soo Lee Byung-Gee Kim 《Biotechnology and Bioprocess Engineering》2006,11(4):299-305
Aromaticl-amino acid transaminase is an enzyme that is able to transfer the amino group froml-glutamate to unnatural aromatic α-keto acids to generate α-ketoglutarate and unnatural aromaticl-amino acids, respectively. Enrichment culture was used to isolate thermophilicBacillus sp. T30 expressing this enzyme for use in the synthesis of unnaturall-amino acids. The asymmetric syntheses ofl-homophenylalanine andl-phenylglycine resulted in conversion yields of >95% and >93% from 150 mM 2-oxo-4-phenylbutyrate and phenylglyoxylate, respectively,
usingl-glutamate as an amino donor at 60°C. Synthesizedl-homophenylalanine andl-phenylglycine were optically pure (>99% enantiomeric excess) and continuously pre-cipitated in the reaction solution due
to their low solubility at the given reaction pH. While the solubility of the α-keto acid substrates is dependent on temperature,
the solubility of the unnaturall-amino acid products is dependent on the reaction pH. As the solubility difference between substrate and product at the given
reaction pH is therefore larger at higher temperature, the thermophilic transaminase was successfully used to shift the reaction
equilibrium toward rapid product formation. 相似文献
6.
Gen-Hai Zhao Hui Li Wei Liu Wei-Guo Zhang Fei Zhang Qian Liu Qing-Cai Jiao 《Amino acids》2011,40(1):215-220
In this research, an improved method for preparation of optically pure β-hydroxy-α-amino acids, catalyzed by serine hydroxymethyl
transferase with threonine aldolase activity, is reported. Using recombinant serine hydroxymethyl transferase (SHMT), an enzymatic
resolution process was established. A series of new substrates, β-phenylserine, β-(nitrophenyl) serine and β-(methylsulfonylphenyl)
serine were used in the resolution process catalyzed by immobilized Escherichia coli cells with SHMT activity. It was observed that the K
m for l-threonine was 28-fold higher than that for l-allo-threonine, suggesting that this enzyme can be classified as a low-specificity l-allo-threonine aldolase. The results also shows that SHMT activity with β-phenylserine as substrate was about 1.48-fold and 1.25-fold
higher than that with β-(methylsulfonylphenyl) serine and β-(nitrophenyl) serine as substrate, respectively. Reaction conditions
were optimized by using 200 mmol/l β-hydroxy-α-amino acid, and 0.1 g/ml of immobilized SHMT cells at pH 7.5 and 45°C. Under
these conditions, the immobilized cells were continuously used 10 times, yielding an average conversion rate of 60.4%. Bead
activity did not change significantly the first five times they were used, and the average conversion rate during the first
five instances was 84.1%. The immobilized cells exhibited favourable operational stability. 相似文献
7.
Syldatk C May O Altenbuchner J Mattes R Siemann M 《Applied microbiology and biotechnology》1999,51(3):293-309
Hydantoinases are valuable enzymes for the production of optically pure d- and l-amino acids. They catalyse the reversible hydrolytic ring cleavage of hydantoin or 5′-monosubstituted hydantoins and are
therefore classified in the EC nomenclature as cyclic amidases (EC 3.5.2.). In the EC nomenclature, four different hydantoin-cleaving
enzymes are described: dihydropyrimidinase (3.5.2.2), allantoinase (EC 3.5.2.5), carboxymethylhydantoinase (EC 3.5.2.4), and
N-methylhydantoinase (EC 3.5.2.14). Beside these, other hydantoinases with known metabolic functions, such as imidase and carboxyethylhydantoinase
and enzymes with unknown metabolic function, are described in the literature and have not yet been classified. An important
question is whether the distinct hydantoinases, which are frequently classified as l-, d-, and non-selective hydantoinases depending on their substrate specificity and stereoselectivity, are related to each other.
In order to investigate the evolutionary relationship, amino acid sequence data can be used for a phylogenetic analysis. Although
most of these enzymes only share limited sequence homology (identity<15%) and therefore are only distantly related, it can
be shown (i) that most of them are members of a broad set of amidases with similarities to ureases and build a protein superfamily,
whereas ATP-dependent hydantoinases are not related, (ii) that the urease-related amidases have evolved divergently from a
common ancestor and (iii) that they share a metal-binding motif consisting of conserved histidine residues. The difference
in enantioselectivity used for the classification of hydantoinases on the basis of their biotechnological value does not reflect
their evolutionary relationship, which is to a more diverse group of enzymes than was assumed earlier. This protein superfamily
probably has its origin in the prebiotic conditions of the primitive earth.
Received: 24 August 1998 / Received revision: 9 November 1998 / Accepted: 21 November 1998 相似文献
8.
Loredano Pollegioni Paolo Motta Gianluca Molla 《Applied microbiology and biotechnology》2013,97(21):9323-9341
l-Amino acid oxidase (LAAO) is a flavoenzyme containing non-covalently bound flavin adenine dinucleotide, which catalyzes the stereospecific oxidative deamination of l-amino acids to α-keto acids and also produces ammonia and hydrogen peroxide via an imino acid intermediate. LAAOs purified from snake venoms are the best-studied members of this family of enzymes, although a number of LAAOs from bacterial and fungal sources have been also reported. From a biochemical point of view, LAAOs from different sources are distinguished by molecular mass, substrate specificity, post-translational modifications and regulation. In analogy to the well-known biotechnological applications of d-amino acid oxidase, important results are expected from the availability of suitable LAAOs; however, these expectations have not been fulfilled yet because none of the “true” LAAOs has successfully been expressed as a recombinant protein in prokaryotic hosts, such as Escherichia coli. In enzyme biotechnology, recombinant production of a protein is mandatory both for the production of large amounts of the catalyst and to improve its biochemical properties by protein engineering. As an alternative, flavoenzymes active on specific l-amino acids have been identified, e.g., l-aspartate oxidase, l-lysine oxidase, l-phenylalanine oxidase, etc. According to presently available information, amino acid oxidases with “narrow” or “strict” substrate specificity represent as good candidates to obtain an enzyme more suitable for biotechnological applications by enlarging their substrate specificity by means of protein engineering. 相似文献
9.
Masumi Katane Yasuaki Saitoh Kazuhiro Maeda Toshihiko Hanai Masae Sekine Takemitsu Furuchi Hiroshi Homma 《Amino acids》2011,40(2):467-476
d-Aspartate oxidase (DDO) and d-amino acid oxidase (DAO) are flavin adenine dinucleotide-containing flavoproteins that catalyze the oxidative deamination
of d-amino acids. Unlike DAO, which acts on several neutral and basic d-amino acids, DDO is highly specific for acidic d-amino acids. Based on molecular modeling and simulated annealing docking analyses, a recombinant mouse DDO carrying two substitutions
(Arg-216 to Leu and Arg-237 to Tyr) was generated (R216L-R237Y variant). This variant and two previously constructed single-point
mutants of mouse DDO (R216L and R237Y variants) were characterized to investigate the role of Arg-216 and Arg-237 in the substrate
specificity of mouse DDO. The R216L-R237Y and R216L variants acquired a broad specificity for several neutral and basic d-amino acids, and showed a considerable decrease in activity against acidic d-amino acids. The R237Y variant, however, did not show any additional specificity for neutral or basic d-amino acids and its activity against acidic d-amino acids was greatly reduced. The kinetic properties of these variants indicated that the Arg-216 residue is important
for the catalytic activity and substrate specificity of mouse DDO. However, Arg-237 is, apparently, only marginally involved
in substrate recognition, but is important for catalytic activity. Notably, the substrate specificity of the R216L-R237Y variant
differed significantly from that of the R216L variant, suggesting that Arg-237 has subsidiary effects on substrate specificity.
Additional experiments using several DDO and DAO inhibitors also suggested the involvement of Arg-216 in the substrate specificity
and catalytic activity of mouse DDO and that Arg-237 is possibly involved in substrate recognition by this enzyme. Collectively,
these results indicate that Arg-216 and Arg-237 play crucial and subsidiary role(s), respectively, in the substrate specificity
of mouse DDO. 相似文献
10.
d-Amino acid N-acetyltransferase is a unique enzyme of Saccharomyces cerevisiae acting specifically on d-amino acids. The enzyme was found to be encoded by HPA3, a putative histone/protein acetyltransferase gene, and we purified its gene product, Hpa3p, from recombinant Escherichia coli cells. Hpa3p shares 49% sequence identity and 81% sequence similarity with a histone acetyltransferase, Hpa2p, of S. cerevisiae. Hpa3p acts on a wide range of d-amino acids but shows extremely low activity toward histone. However, Hpa2p does not act on any of the free amino acids except l-lysine and d-lysine. Kinetic analyses suggest that Hpa3p catalyzes the N-acetylation of d-amino acids through an ordered bi-bi mechanism, in which acetyl-CoA is the first substrate to be bound and CoA is the last product to be liberated. 相似文献
11.
J. Q. Liu S. Ito T. Dairi N. Itoh S. Shimizu H. Yamada 《Applied microbiology and biotechnology》1998,49(6):702-708
Low-specificity l-threonine aldolase, catalyzing the reversible cleavage/condensation reaction between l-threonine/l-allo-threonine and glycine plus acetaldehyde, was purified to homogeneity from Pseudomonas sp. NCIMB 10558. The enzyme has an apparent molecular mass of approximately 145 kDa and consists of four identical subunits
with a molecular mass of 38 kDa. The enzyme, requiring pyridoxal- 5′-phosphate as a coenzyme, is strictly l-specific at the α position, whereas it can not distinguish between threo and erythro forms at the β position. Besides the reversible cleavage/condensation of threonine, the enzyme also catalyzes the reversible
interconversion between glycine plus various aldehydes and l-β-hydroxy-α-amino acids, including l-β-(3,4-dihydroxyphenyl)serine, l-β-(3,4-met‐hylenedioxyphenyl)serine and l-β-phenylserine, providing a new route for the industrial production of these important amino acids.
Received: 10 November 1997 / Received revision: 7 January 1998 / Accepted 30 January 1998 相似文献
12.
Gas chromatographic determination of amino acid enantiomers in bottled and aged wines 总被引:1,自引:0,他引:1
Free l- and d-amino acids were determined by chiral GC-MS in 26 wines, comprising white wines, red wines, ice wines and sparkling wines.
The aim of the work was to investigate whether quantities and pattern of d-amino acids, in particular d-proline, correlate with the storage time of bottled wines. The relative quantities with respect to the corresponding l-enantiomer ranged in white wines from 0.4 to 3.9% d-Ala, 0.9–8.3% d-Asx, and 0.5–8.9% d-Glx, in red wines from 2.9 to 10.6% d-Ala, 2.2–10.9% d-Asx, and 3.9–7.4% d-Glx, and in sparkling wines from 2.2 to 9.8% d-Ala, 2.1–4.4% d-Asx and 1.3–6.1% d-Glx. Low relative quantities of 0.3–0.7% d-Pro were detected in three white wines stored for more than 20 years and did not exceed 0.2% d-Pro in two red wines stored for 10 and 20 years, respectively. An ice wine stored for 24 years contained 0.9% d-Pro, 6.4% d-Glx, 3.0% d-Asp and 1.5% d-Ala. The data confirm the presence of d-amino acids in wines. They do not provide evidence for a correlation between the storage time of bottled wines and quantities
of d-amino acids. 相似文献
13.
Broad specificity amino acid racemase (E.C. 5.1.1.10) from Pseudomonas putida IFO 12996 (BAR) is a unique racemase because of its broad substrate specificity. BAR has been considered as a possible catalyst
which directly converts inexpensive l-amino acids to dl-amino acid racemates. The gene encoding BAR was cloned to utilize BAR for the synthesis of d-amino acids, especially d-Trp which is an important intermediate of pharmaceuticals. The substrate specificity of cloned BAR covered all of the standard
amino acids; however, the activity toward Trp was low. Then, we performed random mutagenesis on bar to obtain mutant BAR derivatives with high activity for Trp. Five positive mutants were isolated after the two-step screening
of the randomly mutated BAR. After the determination of the amino acid substitutions in these mutants, it was suggested that
the substitutions at Y396 and I384 increased the Trp specific racemization activity and the racemization activity for overall
amino acids, respectively. Among the positive mutants, I384M mutant BAR showed the highest activity for Trp. l-Trp (20 mM) was successfully racemized, and the proportion of d-Trp was reached 43% using I384M mutant BAR, while wild-type BAR racemized only 6% of initial l-Trp. 相似文献
14.
In the skin of fire-bellied toads (Bombina species), an aminoacyl-l/d-isomerase activity is present which catalyses the post-translational isomerization of the l- to the d-form of the second residue of its substrate peptides. Previously, this new type of enzyme was studied in some detail and
genes potentially coding for similar polypeptides were found to exist in several vertebrate species including man. Here, we
present our studies to the substrate specificity of this isomerase using fluorescence-labeled variants of the natural substrate
bombinin H with different amino acids at positions 1, 2 or 3. Surprisingly, this enzyme has a rather low selectivity for residues
at position 2 where the change of chirality at the alpha-carbon takes place. In contrast, a hydrophobic amino acid at position
1 and a small one at position 3 of the substrate are essential. Interestingly, some peptides containing a Phe at position
3 also were substrates. Furthermore, we investigated the role of the amino-terminus for substrate recognition. In view of
the rather broad specificity of the frog isomerase, we made a databank search for potential substrates of such an enzyme.
Indeed, numerous peptides of amphibia and mammals were found which fulfill the requirements determined in this study. Expression
of isomerases with similar characteristics in other species can therefore be expected to catalyze the formation of peptides
containing d-amino acids. 相似文献
15.
l-Amino acid dehydrogenases are a group of enzymes that catalyze the reversible oxidative deamination of l-amino acids to their corresponding 2-oxoacids, using either nicotinamide adenine dinucleotide (NAD+) or nicotinamide adenine dinucleotide phosphate (NADP+) as cofactors. These enzymes have been studied widely because of their potential applications in the synthesis of amino acids
for use in production of pharmaceutical peptides, herbicides and insecticides, in biosensors or diagnostic kits, and development
of coenzyme regeneration systems for industrial processes. This article presents a review of the currently available data
about the recently discovered amino acid dehydrogenase superfamily member l-aspartate dehydrogenase (l-AspDH), their relevant catalytic properties and speculated physiological roles, and potential for biotechnological applications.
The proposed classification of l-AspDH on the basis of bioinformatic information and potential role in vivo into NadB (NAD biosynthesis-related) and non-NadB
type is unique. In particular, the mesophilic non-NadB type l-AspDH is a novel group of amino acid dehydrogenases with great promise as potential industrial biocatalysts owing to their
relatively high catalytic properties at room temperature. Considering that only a few l-AspDH homologs have been characterized so far, identification and prodigious enzymological research of the new members will
be necessary to shed light on the gray areas pertaining to these enzymes. 相似文献
16.
Nutritional and medicinal aspects of <Emphasis Type="SmallCaps">d</Emphasis>-amino acids 总被引:2,自引:0,他引:2
This paper reviews and interprets a method for determining the nutritional value of d-amino acids, d-peptides, and amino acid derivatives using a growth assay in mice fed a synthetic all-amino acid diet. A large number of
experiments were carried out in which a molar equivalent of the test compound replaced a nutritionally essential amino acid
such as l-lysine (l-Lys), l-methionine (l-Met), l-phenylalanine (l-Phe), and l-tryptophan (l-Trp) as well as the semi-essential amino acids l-cysteine (l-Cys) and l-tyrosine (l-Tyr). The results show wide-ranging variations in the biological utilization of test substances. The method is generally
applicable to the determination of the biological utilization and safety of any amino acid derivative as a potential nutritional
source of the corresponding l-amino acid. Because the organism is forced to use the d-amino acid or amino acid derivative as the sole source of the essential or semi-essential amino acid being replaced, and
because a free amino acid diet allows better control of composition, the use of all-amino-acid diets for such determinations
may be preferable to protein-based diets. Also covered are brief summaries of the widely scattered literature on dietary and
pharmacological aspects of 27 individual d-amino acids, d-peptides, and isomeric amino acid derivatives and suggested research needs in each of these areas. The described results
provide a valuable record and resource for further progress on the multifaceted aspects of d-amino acids in food and biological samples. 相似文献
17.
Yan Zhen Mei Bing Fang He Ping Kai Ouyang 《World journal of microbiology & biotechnology》2008,24(3):375-381
Bacillus fordii MH602 was newly screened from soil at 45 °C and exhibited high activities of hydantoinase and carbamoylase, efficiently yielding
l-amino acids including phenylalanine, phenylglycine and tryptophan with the bioconversion yield of 60–100% from the corresponding
dl-5-substituted hydantoins. Hydantoinase activity was found to be cell-associated and inducible. The optimal inducer was dl-5-methylhydantoin with concentration of 0.014 mol L−1 and added to the fermentation medium in the exponential phase of growth. In the production of optically pure amino acids
from dl-5-benylhydantoin, the optimal temperature and pH of this reaction were 45–50 °C and 7.5 respectively. The hydantoinase was
non-stereoselective, while carmbamoylase was l-selective. The hydantoinase activity was not subject to substrate inhibition, or product inhibition by ammonia. In addition,
The activities of both enzymes from crude extract of the strain were thermostable; the hydantoinase and carbamoylase retained
about 90% and 60% activity after 6 h at 50 °C, respectively. Since reaction at higher temperature is advantageous for enhancement
of solubility and for racemization of dl-5-substituted hydantoins, the relative paucity of l-selective hydantoinase systems, together with the high level of hydantoinase and carbamoylase activity and unusual substrate
selectivity of the strain MH602, suggest that it has significant potential applications. 相似文献
18.
Thomas Haack Ma. José González Yolanda Sánchez Ernest Giralt 《International journal of peptide research and therapeutics》1997,4(4-6):377-386
Summary With a few exceptions, proteins in our biosphere are based exclusively onl-amino acids. The inversion of configuration of all the stereogenic centers in a protein leads to anall-d compound with ‘mirror image’ properties and ‘mirror image’ structure. We propose to use the termprotein-enantiomerism to describe the relationship between two proteins that have the same sequence but whose amino acids have opposite configuration.
We will use the termprotein-diastereomerism to define the relationship between two proteins that have the same sequence in which some amino acids have opposite configurations.
A classification of type I, II, III, and IV protein-diastereomerism is proposed. By extension, a diastereoprotein is a protein
where some amino acids have the same configuration (l ord) while others have the opposite one (d orl). A particular case of diastereoproteins aremesoproteins, also analyzed in this article. In addition to the goal of making proteins resistant to protease degradation, the use ofd-amino acids in protein de novo design may give rise to proteins with structures, and perhaps properties, very different to
those of nativeall-l-proteins. 相似文献
19.
Zhu L Tao R Wang Y Jiang Y Lin X Yang Y Zheng H Jiang W Yang S 《Applied microbiology and biotechnology》2011,90(3):903-910
l-2-Aminobutyric acid can be synthesized in a transamination reaction from l-threonine and l-aspartic acid as substrates by the action of threonine deaminase and aromatic aminotransferase, but the by-product l-alanine was produced simultaneously. A small amount of l-alanine increased the complexity of the l-2-aminobutyric acid recovery process because of their extreme similarity in physical and chemical properties. Acetolactate
synthase has been introduced to remove the pyruvate intermediate for reducing the l-alanine concentration partially. To eliminate the remnant l-alanine, alanine racemase of Bacillus subtilis in combination with d-amino acid oxidase of Rhodotorula gracilis or Trigonopsis variabilis respectively was introduced into the reaction system for the l-2-aminobutyric acid synthesis. l-Alanine could be completely removed by the action of alanine racemase of B. subtilis and d-amino acid oxidase of R. gracilis; thereby, high-purity l-2-aminobutyric acid was achieved. The results revealed that alanine racemase could discriminate effectively between l-alanine and l-2-aminobutyric acid, and selectively catalyzed l-alanine to d-alanine reversibly. d-Amino acid oxidase then catalyzed d-alanine to pyruvate stereoselectively. Furthermore, this method was also successfully used to remove the by-product l-alanine in the production of other neutral amino acids such as l-tertiary leucine and l-valine, suggesting that multienzymatic whole-cell catalysis can be employed to provide high purity products. 相似文献
20.
In Nocardia sp. 239 d-phenylalanine is converted into l-phenylalanine by an inducible amino acid racemase. The further catabolism of this amino acid involves an NAD-dependent l-phenylalanine dehydrogenase. This enzyme was detected only in cells grown on l- or d-phenylalanine and in batch cultures highest activities were obtained at relatively low amino acid concentrations in the medium. The presence of additional carbon- or nitrogen sources invariably resulted in decreased enzyme levels. From experiments with phenylalanine-limited continuous cultures it appeared that the rate of synthesis of the enzyme increased with increasing growth rates. The regulation of phenylalanine dehydrogenase synthesis was studied in more detail during growth of the organism on mixtures of methanol and l-phenylalanine. Highest rates of l-phenylalanine dehydrogenase production were observed with increasing ratios of l-phenylalanine/methanol in the feed of chemostat cultures. Characteristic properties of the enzyme were investigated following its (partial) purification from l- and d-phenylalanine-grown cells. This resulted in the isolation of enzymes with identical properties. The native enzyme had a molecular weight of 42 000 and consisted of a single subunit; it showed activity with l-phenylalanine, phenylpyruvate, 4-hydroxyphenyl-pyruvate, indole-3-pyruvate and -ketoisocaproate, but not with imidazolepyruvate, d-phenylalanine and other l-amino acids tested. Maximum activities with phenylpyruvate (310 mol min-1 mg-1 of purified protein) were observed at pH 10 and 53°C. Sorbitol and glycerol stabilized the enzyme.Abbreviations RuMP
ribulose monophosphate
- HPS
hexulose-6-phosphate synthase
- HPT
hexulose-6-phosphate isomerase
- FPLC
fast protein liquid chromatography 相似文献