共查询到20条相似文献,搜索用时 46 毫秒
1.
Paweł Wiśniewski Justyna Szklarczyk Marcin Maciaga Andrzej Paszkowski 《Acta Physiologiae Plantarum》2006,28(6):577-588
The occurrence of four l-alanine:2-oxoglutarate aminotransferase (AOAT) isoenzymes (AOAT-like proteins): alanine aminotransferase 1 and 2 (AlaAT1
and AlaAT2, EC 2.6.1.2) and l-glutamate:glyoxylate aminotransferase 1 and 2 (GGAT1 and GGAT2, EC 2.6.1.4) was demonstrated in Arabidopsis thaliana leaves. These enzymes differed in their substrate specificity, susceptibility to pyridoxal phosphate inhibitors and behaviour
during molecular sieving on Zorbax SE-250 column. A difference was observed in the electrostatic charge values at pH 9.1 between
GGAT1 and GGAT2 as well as between AlaAT1 and AlaAT2, despite high levels of amino acid sequence identity (93 % and 85 %,
respectively). The unprecedented evidence for the monomeric structure of both AlaAT1 and AlaAT2 is presented. The molecular
mass of each enzyme estimated by molecular sieving on Sephadex G-150 and Zorbax SE-250 columns and SDS/PAGE was approximately
60 kDa. The kinetic parameters: Km (Ala)=1.53 mM, Km (2-oxoglutarate)=0.18 mM, kcat=124.6 s−1, kcat/Km=8.1 × 104 M−1·s−1 of AlaAT1 were comparable to those determined for other AlaATs isolated from different sources. The two studied GGATs also
consisted of a single subunit with molecular mass of 47.3–70 kDa. The estimated Km values for l-glutamate (1.2 mM) and glyoxylate (0.42 mM) in the transamination catalyzed by putative GGAT1 contributed to indentification
of the enzyme. Based on these results we concluded that each of four AOAT genes in Arabidopsis thaliana leaves expresses different AOAT isoenzyme, functioning in a native state as a monomer. 相似文献
2.
Soo-Jin Yeom Nam-Hee Kim Ran-Young Yoon Hyun-Jung Kwon Chang-Su Park Deok-Kun Oh 《Biotechnology letters》2009,31(8):1273-1278
A recombinant mannose-6-phosphate isomerase from Geobacillus thermodenitrificans (GTMpi) isomerizes aldose substrates possessing hydroxyl groups oriented in the same direction at the C2 and C3 positions
such as the d- and l-forms of ribose, lyxose, talose, mannose, and allose. The activity of GTMpi for d-lyxose isomerization was optimal at pH 7.0, 70°C and 1 mM Co2+. Under these conditions, the k
cat and K
m values were 74,300 s−1 and 390 mM for d-lyxose and 28,800 s−1 and 470 mM for l-ribose, respectively. The half-lives of the enzyme at 60, 65, and 70°C were 388, 73, and 27 h, respectively. GTMpi catalyzed
the conversion of d-lyxose to d-xylulose with a 38% conversion yield after 3 h, and converted l-ribose to l-ribulose with a 29% conversion yield. 相似文献
3.
Poonperm W Takata G Okada H Morimoto K Granström TB Izumori K 《Applied microbiology and biotechnology》2007,76(6):1297-1307
The l-rhamnose isomerase gene (L
-rhi) encoding for l-rhamnose isomerase (l-RhI) from Bacillus pallidus Y25, a facultative thermophilic bacterium, was cloned and overexpressed in Escherichia coli with a cooperation of the 6×His sequence at a C-terminal of the protein. The open reading frame of L
-rhi consisted of 1,236 nucleotides encoding 412 amino acid residues with a calculated molecular mass of 47,636 Da, showing a
good agreement with the native enzyme. Mass-produced l-RhI was achieved in a large quantity (470 mg/l broth) as a soluble protein. The recombinant enzyme was purified to homogeneity
by a single step purification using a Ni-NTA affinity column chromatography. The purified recombinant l-RhI exhibited maximum activity at 65°C (pH 7.0) under assay conditions, while 90% of the initial enzyme activity could be
retained after incubation at 60°C for 60 min. The apparent affinity (K
m) and catalytic efficiency (k
cat/K
m) for l-rhamnose (at 65°C) were 4.89 mM and 8.36 × 105 M−1 min−1, respectively. The enzyme demonstrated relatively low levels of amino acid sequence similarity (42 and 12%), higher thermostability,
and different substrate specificity to those of E. coli and Pseudomonas stutzeri, respectively. The enzyme has a good catalyzing activity at 50°C, for d-allose, l-mannose, d-ribulose, and l-talose from d-psicose, l-fructose, d-ribose and l-tagatose with a conversion yield of 35, 25, 16 and 10%, respectively, without a contamination of by-products. These findings
indicated that the recombinant l-RhI from B. pallidus is appropriate for use as a new source of rare sugar producing enzyme on a mass scale production. 相似文献
4.
A recombinant putative glycoside hydrolase from Caldicellulosiruptor saccharolyticus was purified with a specific activity of 12 U mg−1 by heat treatment and His-Trap affinity chromatography, and identified as a single 56 kDa band upon SDS-PAGE. The native
enzyme is a dimer with a molecular mass of 112 kDa as determined by gel filtration. The enzyme exhibited its highest activity
when debranched arabinan (1,5-α-l-arabinan) was used as the substrate, demonstrating that the enzyme was an endo-1,5-α-l-arabinanase. The K
m, k
cat, and k
cat/K
m values were 18 mg ml−1, 50 s−1, and a 2.8 mg ml−1 s−1, respectively. Maximum enzyme activity was at pH 6.5 and 75°C. The half-lives of the enzyme at 65, 70 and 75°C were 2440,
254 and 93 h, respectively, indicating that it is the most thermostable of the known endo-1,5-α-l-arabinanases. 相似文献
5.
Syntheses of l-dopa 1a glucoside 10a,b and dl-dopa 1b glycosides 10–18 with d-glucose 2, d-galactose 3, d-mannose 4, d-fructose 5, d-arabinose 6, lactose 7, d-sorbitol 8 and d-mannitol 9 were carried out using amyloglucosidase from Rhizopus mold, β-glucosidase isolated from sweet almond and immobilized β-glucosidase. Invariably, l-dopa and dl-dopa gave low to good yields of glycosides 10–18 at 12–49% range and only mono glycosylated products were detected through glycosylation/arylation at the third or fourth
OH positions of l-dopa 1a and dl-dopa 1b. Amyloglucosidase showed selectivity with d-mannose 4 to give 4-O-C1β and d-sorbitol 8 to give 4-O-C6-O-arylated product. β-Glucosidase exhibited selectivity with d-mannose 4 to give 4-O-C1β and lactose 7 to give 4-O-C1β product. Immobilized β-glucosidase did not show any selectivity. Antioxidant and angiotensin converting enzyme inhibition
(ACE) activities of the glycosides were evaluated glycosides, out of which l-3-hydroxy-4-O-(β-d-galactopyranosyl-(1′→4)β-d-glucopyranosyl) phenylalanine 16 at 0.9 ± 0.05 mM and dl-3-hydroxy-4-O-(β-d-glucopyranosyl) phenylalanine 11b,c at 0.98 ± 0.05 mM showed the best IC50 values for antioxidant activity and dl-3-hydroxy-4-O-(6-d-sorbitol)phenylalanine 17 at 0.56 ± 0.03 mM, l-dopa-d-glucoside 10a,b at 1.1 ± 0.06 mM and dl-3-hydroxy-4-O-(d-glucopyranosyl)phenylalanine 11a-d at 1.2 ± 0.06 mM exhibited the best IC50 values for ACE inhibition.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
6.
Corynebacterium glutamicum R was metabolically engineered to broaden its sugar utilization range to d-xylose and d-cellobiose contained in lignocellulose hydrolysates. The resultant recombinants expressed Escherichia coli xylA and xylB genes, encoding d-xylose isomerase and xylulokinase, respectively, for d-xylose utilization and expressed C. glutamicum R bglF
317A
and bglA genes, encoding phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) β-glucoside-specific enzyme IIBCA component
and phospho-β-glucosidase, respectively, for d-cellobiose utilization. The genes were fused to the non-essential genomic regions distributed around the C. glutamicum R chromosome and were under the control of their respective constitutive promoter trc and tac that permitted their expression even in the presence of d-glucose. The enzyme activities of resulting recombinants increased with the increase in the number of respective integrated
genes. Maximal sugar utilization was realized with strain X5C1 harboring five xylA–xylB clusters and one bglF
317A
–bglA cluster. In both d-cellobiose and d-xylose utilization, the sugar consumption rates by genomic DNA-integrated strain were faster than those by plasmid-bearing
strain, respectively. In mineral medium containing 40 g l−1
d-glucose, 20 g l−1
d-xylose, and 10 g l−1
d-cellobiose, strain X5C1 simultaneously and completely consumed these sugars within 12 h and produced predominantly lactic
and succinic acids under growth-arrested conditions. 相似文献
7.
M. Helanto K. Kiviharju T. Granström M. Leisola A. Nyyssölä 《Applied microbiology and biotechnology》2009,83(1):77-83
l-Ribose is a rare and expensive sugar that can be used as a precursor for the production of l-nucleoside analogues, which are used as antiviral drugs. In this work, we describe a novel way of producing l-ribose from the readily available raw material l-arabinose. This was achieved by introducing l-ribose isomerase activity into l-ribulokinase-deficient Escherichia coli UP1110 and Lactobacillus plantarum BPT197 strains. The process for l-ribose production by resting cells was investigated. The initial l-ribose production rates at 39°C and pH 8 were 0.46 ± 0.01 g g−1 h−1 (1.84 ± 0.03 g l−1 h−1) and 0.27 ± 0.01 g g−1 h−1 (1.91 ± 0.1 g l−1 h−1) for E. coli and for L. plantarum, respectively. Conversions were around 20% at their highest in the experiments. Also partially purified protein precipitates
having both l-arabinose isomerase and l-ribose isomerase activity were successfully used for converting l-arabinose to l-ribose. 相似文献
8.
l-arabinose isomerase (EC5.3.1.4. AI) mediates the isomerization of d-galactose into d-tagatose as well as the conversion of l-arabinose into l-ribulose. The AI from Lactobacillus plantarum SK-2 was purified to an apparent homogeneity giving a single band on SDS–PAGE with a molecular mass of 59.6 kDa. Optimum
activity was observed at 50°C and pH 7.0. The enzyme was stable at 50°C for 2 h and held between pH 4.5 and 8.5 for 1 h. AI
activity was stimulated by Mn2+, Fe3+, Fe2+, Ca2+ and inhibited by Cu2+, Ag+, Hg2+, Pb2+. d-galactose and l-arabinose as substrates were isomerized with high activity. l-arabitol was the strongest competitive inhibitor of AI. The apparent Michaelis–Menten constant (K
m), for galactose, was 119 mM. The first ten N-terminal amino acids of the enzyme were determined as MLSVPDYEFW, which is identical to L. plantarum (Q88S84). Using the purified AI, 390 mg tagatose could be converted from 1,000 mg galactose in 96 h, and this production
corresponds to a 39% equilibrium. 相似文献
9.
Sebastián Sánchez Vicente Bravo Juan Francisco García Nicolás Cruz Manuel Cuevas 《World journal of microbiology & biotechnology》2008,24(5):709-716
The fermentation of d-glucose and d-xylose mixtures by the yeast Candida tropicalis NBRC 0618 has been studied under the most favourable operation conditions for the culture, determining the most adequate
initial proportion in these sugars for xylitol production. In all the experiments a synthetic culture medium was used, with
an initial total substrate concentration of 25 g L−1, a constant pH of 5.0 and a temperature of 30 °C. From the experimental results, it was deduced that the highest values of
specific rates of production and of overall yield in xylitol were achieved for the mixtures with the highest percentage of
d-xylose, specifically in the culture with the initial d-glucose and d-xylose concentrations of 1 and 24 g L−1, respectively, with an overall xylitol yield of 0.28 g g−1. In addition, the specific rates of xylitol production declined over the time course of the culture and the formation of
this bioproduct was favoured by the presence of small quantities of d-glucose. The sum of the overall yield values in xylitol and ethanol for all the experiments ranged from 0.26 to 0.56 g bioproduct/g
total substrate. 相似文献
10.
Unlike other yeasts so far investigated, the d-glucose carrier of Candida utilis (strain NCYC 737) appears to change affinity for d-glucose according to its exogenous concentration. When the concentration of d-glucose was <0.4 mM, the apparent K
m 0.2 mM; at >0.4 mM, the K
m 10 mM. 相似文献
11.
The rpiB gene, encoding ribose-5-phosphate isomerase (RpiB) from Clostridium thermocellum, was cloned and expressed in Escherichia coli. RpiB converted d-psicose into d-allose but it did not convert d-xylose, l-rhamnose, d-altrose or d-galactose. The production of d-allose by RpiB was maximal at pH 7.5 and 65°C for 30 min. The half-lives of the enzyme at 50°C and 65°C were 96 h and 4.7 h,
respectively. Under stable conditions of pH 7.5 and 50°C, 165 g d-allose l−1
was produced without by-products from 500 g d-psicose l−1 after 6 h. 相似文献
12.
A non-characterized gene, previously proposed as the d-tagatose-3-epimerase gene from Rhodobacter sphaeroides, was cloned and expressed in Escherichia coli. Its molecular mass was estimated to be 64 kDa with two identical subunits. The enzyme specificity was highest with d-fructose and decreased for other substrates in the order: d-tagatose, d-psicose, d-ribulose, d-xylulose and d-sorbose. Its activity was maximal at pH 9 and 40°C while being enhanced by Mn2+. At pH 9 and 40°C, 118 g d-psicose l−1 was produced from 700 g d-fructose l−1 after 3 h.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
13.
Verónica Beatriz Rajal Alicia Graciela Cid Guillermo Ellenrieder Carlos Mario Cuevas 《World journal of microbiology & biotechnology》2009,25(6):1025-1033
Penicillium ulaiense is a post-harvest pathogenic fungus that attacks citrus fruits. The objective of this work was to study this microorganism
as an α-l-rhamnosidase producer and to characterize it from P. ulaiense. The enzyme under study is used for different applications in food and beverage industries. α-l-Rhamnosidase was produced in a stirred-batch reactor using rhamnose as the main carbon source. The kinetic parameters for
the growth of the fungi and for the enzyme production were calculated from the experimental values. A method for partial purification,
including (NH4)2SO4 precipitation, incubation at pH 12 and DEAE-sepharose chromatography yielded an enzyme with very low β-glucosidase activity.
The pH and temperature optima were 5.0 and 60°C, respectively. The Michaelis–Menten constants for the hydrolysis of p-nitrophenyl-α-l-rhamnoside were V
max = 26 ± 4 IU ml−1 and K
m
= 11 ± 2 mM. The enzyme showed good thermostability up to 60°C and good operational stability in white wine. Co2+ affected positively the activity; EDTA, Mn2+, Mg2+, dithiotreitol and Cu2+ reduced the activity by different amounts, and Hg2+ completely inhibited the enzyme. The enzyme showed more activity on p-nitrophenyl-α-l-rhamnoside than on naringin. According to these results, this enzyme has potential for use in the food and pharmacy industries
since P. ulaiense does not produce mycotoxins. 相似文献
14.
d-Mannitol-1-phosphate dehydrogenase (EC 1.1.1.17) and d-mannitol dehydrogenase (EC 1.1.1.67) were estimated in a cell-free extract of the unicellular alga Platymonas subcordiformis Hazen (Prasinophyceae), d-Mannitol dehydrogenase had two activity maxima at pH 7.0 and 9.5, and a substrate specifity for d-fructose and NADH or for d-mannitol and NAD+. The K
m values were 43 mM for d-fructose and 10 mM for d-mannitol. d-Mannitol-1-phosphate dehydrogenase had a maximum activity at pH 7.5 and was specific for d-fructose 6-phosphate and NADH. The K
m value for d-fructose 6-phosphate was 5.5 mM. The reverse reaction with d-mannitol 1-phosphate as substrate could not be detected in the extract. After the addition of NaCl (up to 800 mM) to the enzyme assay, the activity of d-mannitol dehydrogenase was strongly inhibited while the activity of d-mannitol-1-phosphate dehydrogenase was enhanced. Under salt stress the K
m values of the d-mannitol dehydrogenase were shifted to higher values. The K
m value for d-fructose 6-phosphate as substrate for d-mannitol-1-phosphate dehydrogenase remained constant. Hence, it is concluded that in Platymonas the d-mannitol pool is derectly regulated via alternative pathways with different activities dependent on the osmotic pressure.Abbreviations Fru6P
d-fructose 6-phosphate
- Mes
2-(N-morpholino)ethanesulfonic acid
- MT-DH
d-mannitol-dehydrogenase
- MT1P-DH
d-mannitol-1-phosphate dehydrogenase
- Pipes
1,4-piperazinediethanesulfonic acid
- Tris
2-amino-2-(hydroxymethyl)-1,3-propanediol 相似文献
15.
Muller AP Rotta LN Kawano C Leszczinski DN Schweigert ID Londero LG Gravina FS da Silveira CK de Souza CG Battu CE Gonçalves CA de Souza DO Perry ML 《Neurochemical research》2006,31(3):417-422
We studied the effect of different concentrations of 2-deoxy-d-glucose on the l-[U-14C]leucine, l-[1-14C]leucine and [1-14C]glycine metabolism in slices of cerebral cortex of 10-day-old rats. 2-deoxy-d-glucose since 0.5 mM concentration has inhibited significantly the protein synthesis from l-[U-14C]leucine and from [1-14C]glycine in relation to the medium containing only Krebs Ringer bicarbonate. Potassium 8.0 mM in incubation medium did not stimulate the protein synthesis compared to the medium containing 2.7 mM, and at 50 mM diminishes more than 2.5 times the protein synthesis compared to the other concentration. Only at the concentration of 5.0 mM, 2-deoxy-d-glucose inhibited the CO2 production and lipid synthesis from l-[U-14C] leucine. This compound did not inhibit either CO2 production, or lipid synthesis from [1-14C]glycine. Lactate at 10 mM and glucose 5.0 mM did not revert the inhibitory effect of 2-deoxy-d-glucose on the protein synthesis from l-[U-14C]leucine. 2-deoxy-d-glucose at 2.0 mM did not show any effect either on CO2 production, or on lipid synthesis from l-[U-14C]lactate 10 mM and glucose 5.0 mM. 相似文献
16.
Takashi Nemoto Taisuke Watanabe Yutaka Mizogami Jun-ichi Maruyama Katsuhiko Kitamoto 《Applied microbiology and biotechnology》2009,82(6):1105-1114
The recombinant Pichia pastoris harboring an improved methionine adenosyltransferase (MAT) shuffled gene was employed to biosynthesize S-adenosyl-l-methionine (SAM). Two l-methionine (l-Met) addition strategies were used to supply the precursor: the batch addition strategy (l-Met was added separately at three time points) and the continuous feeding strategies (l-Met was fed continuously at the rate of 0.1, 0.2, and 0.5 g l−1 h−1, respectively). SAM accumulation, l-Met conversion rate, and SAM productivity with the continuous feeding strategies were all improved over the batch addition
strategy, which reached 8.46 ± 0.31 g l−1, 41.7 ± 1.4%, and 0.18 ± 0.01 g l−1 h−1 with the best continuous feeding strategy (0.2 g l−1 h−1), respectively. The bottleneck for SAM production with the low l-Met feeding rate (0.1 g L−1 h−1) was the insufficient l-Met supply. The analysis of the key enzyme activities indicated that the tricarboxylic acid cycle and glycolytic pathway
were reduced with the increasing l-Met feeding rate, which decreased the adenosine triphosphate (ATP) synthesis. The MAT activity also decreased as the l-Met feeding rate rose. The reduced ATP synthesis and MAT activity were probably the reason for the low SAM accumulation when
the l-Met feeding rate reached 0.5 g l−1 h−1. 相似文献
17.
Okino S Suda M Fujikura K Inui M Yukawa H 《Applied microbiology and biotechnology》2008,78(3):449-454
In mineral salts medium under oxygen deprivation, Corynebacterium glutamicum exhibits high productivity of l-lactic acid accompanied with succinic and acetic acids. In taking advantage of this elevated productivity, C. glutamicum was genetically modified to produce d-lactic acid. The modification involved expression of fermentative d-lactate dehydrogenase (d-LDH)-encoding genes from Escherichia coli and Lactobacillus delbrueckii in l-lactate dehydrogenase (l-LDH)-encoding ldhA-null C. glutamicum mutants to yield strains C. glutamicum ΔldhA/pCRB201 and C. glutamicum ΔldhA/pCRB204, respectively. The productivity of C. glutamicum ΔldhA/pCRB204 was fivefold higher than that of C. glutamicum ΔldhA/pCRB201. By using C. glutamicum ΔldhA/pCRB204 cells packed to a high density in mineral salts medium, up to 1,336 mM (120 g l−1) of d-lactic acid of greater than 99.9% optical purity was produced within 30 h. 相似文献
18.
Using 3′-RACE and 5′-RACE, we have cloned and sequenced the genomic gene and complete cDNA encoding l-glutamine d-fructose 6-phosphate amidotransferase (GFAT) from the edible straw mushroom, Volvariella volvacea. Gfat contains five introns, and encodes a predicted protein of 697 amino acids that is homologous to other reported GFAT sequences.
Southern hybridization indicated that a single gfat gene locus exists in the V. volvacea genome. Recombinant native V. volvacea GFAT enzyme, over-expressed using Escherichia coli and partially purified, had an estimated molecular mass of 306 kDa and consisted of four equal-sized subunits of 77 kD. Reciprocal
plots revealed K
m values of 0.55 and 0.75 mM for fructose 6-phosphate and l-glutamine, respectively. V. volvacea GFAT activity was inhibited by the end-product of the hexosamine pathway, UDP-GlcNAc, and by the glutamine analogues N
3-(4-methoxyfumaroyl)-l-2,3-diaminopropanoic acid and 2-amino-2-deoxy-d-glucitol-6-phosphate. 相似文献
19.
Prabhu P Tiwari MK Jeya M Gunasekaran P Kim IW Lee JK 《Applied microbiology and biotechnology》2008,81(2):283-290
Based on analysis of the genome sequence of Bacillus licheniformis ATCC 14580, an isomerase-encoding gene (araA) was proposed as an l-arabinose isomerase (L-AI). The identified araA gene was cloned from B. licheniformis and overexpressed in Escherichia coli. DNA sequence analysis revealed an open reading frame of 1,422 bp, capable of encoding a polypeptide of 474 amino acid residues
with a calculated isoelectric point of pH 4.8 and a molecular mass of 53,500 Da. The gene was overexpressed in E. coli, and the protein was purified as an active soluble form using Ni–NTA chromatography. The molecular mass of the purified enzyme
was estimated to be ~53 kDa by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and 113 kDa by gel filtration chromatography,
suggesting that the enzyme is a homodimer. The enzyme required a divalent metal ion, either Mn2+or Co2+, for enzymatic activity. The enzyme had an optimal pH and temperature of 7.5 and 50°C, respectively, with a k
cat of 12,455 min−1 and a k
cat/K
m of 34 min−1 mM−1 for l-arabinose, respectively. Although L-AIs have been characterized from several other sources, B. licheniformis L-AI is distinguished from other L-AIs by its wide pH range, high substrate specificity, and catalytic efficiency for l-arabinose, making B. licheniformis L-AI the ideal choice for industrial applications, including enzymatic synthesis of l-ribulose. This work describes one of the most catalytically efficient L-AIs characterized thus far. 相似文献
20.
A. Corriat N. Moatti A. Lemonnier 《In vitro cellular & developmental biology. Plant》1983,19(7):522-528
Summary The transport ofl-histidine has been characterized in skin derived diploid human fibroblasts, cultured under strictly controlled conditions.
The transport measurements were made on cells grown to subconfluency after 60 to 90 min timed preincubation. The data, at
substrate concentrations ranging from 0.050 to 10 mmol/l, were analyzed by a computer program. A saturable transport system
(K
m
=0.25 mmol/l, V
max
=17 nmol/mg protein per min) and a nonsaturable component of influx (K
d
=1.6±0.4 nmol/mg protein/min per mmol) were found.l-Histidine displayed no Na+ requirement at either low or high concentrations. Inhibition analysis demonstrated thatl-histidine uptake at low concentration was poorly inhibited by amino acids known to be effective inhibitors of system A. The
largest fraction ofl-histidine uptake was inhibited by 2-amino-bicyclo (2,2,1)-heptane-2-carboxylic acid (BCH), leucine, and tryptophan. These
results indicated thatl-histidine is transported in human fibroblasts, mainly by the Na+ independent system L. The differences between this cell type and others studied previously are discussed.
This work was supported in part by Grant 773 from UER de Médecine, Université Paris XI (France). 相似文献