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1.
Summary. Amino acids are widely used in biotechnology applications. Since amino acids are natural compounds, they can be safely used
in pharmaceutical applications, e.g., as a solvent additive for protein purification and as an excipient for protein formulations.
At high concentrations, certain amino acids are found to raise intra-cellular osmotic pressure and adjust to the high salt
concentrations of the surrounding medium. They are called “compatible solutes”, since they do not affect macromolecular function.
Not only are they needed to increase the osmotic pressure, they are known to increase the stability of the proteins. Sucrose,
glycerol and certain amino acids were used to enhance the stability of unstable proteins after isolation from natural environments.
The mechanism of the action of these protein-stabilizing amino acids is relatively well understood. On the contrary, arginine
was accidentally discovered as a useful reagent for assisting in the refolding of recombinant proteins. This effect of arginine
was ascribed to its ability to suppress aggregation of the proteins during refolding, thereby increasing refolding efficiency.
By the same mechanism, arginine now finds much wider applications than previously anticipated in the research and development
of proteins, in particular in pharmaceutical applications. For example, arginine solubilizes proteins from loose inclusion
bodies, resulting in efficient production of active proteins. Arginine suppresses protein–protein interactions in solution
and also non-specific adsorption to gel permeation chromatography columns. Arginine facilitates elution of bound proteins
from various column resins, including Protein-A or dye affinity columns and hydrophobic interaction columns. This review covers
various biotechnology applications of amino acids, in particular arginine. 相似文献
2.
Regulation of apoptosis by protein S-nitrosylation 总被引:1,自引:0,他引:1
Mannick JB 《Amino acids》2007,32(4):523-526
Summary. S-nitrosylation/denitrosylation of critical cysteine residues on proteins serves as a redox switch that regulates the function
of a wide array of proteins. A key signaling pathway that is regulated by S-nitrosylation is apoptotic cell death. Here we
will review the proteins in apoptotic pathways that are known to be S-nitrosylated by endogenous NO production. The targets
and functional consequences of S-nitrosylation during apoptosis are multifaceted, allowing cells to fine tune their response
to apoptotic signals. 相似文献
3.
Summary. The accumulation of oxidized proteins is known to be linked to some severe neurodegenerative diseases like Alzheimer’s, Parkinson’s
and Huntington’s disease. Furthermore, the aging process is also accompanied by an ongoing aggregation of misfolded and damaged
proteins. Therefore, mammalian cells have developed potent degradation systems, which selectively degrade damaged and misfolded
proteins. The proteasomal system is largely responsible for the removal of oxidatively damaged proteins form the cellular
environment. Not only cytosolic proteins are prone to oxidative stress, also nuclear proteins are readily oxidized. The nuclear
proteasomal system is responsible for the degradation of these proteins. This review is focused on the specific degradation
of oxidized nuclear proteins, the role of the proteasome in this process and the regulation of the nuclear proteasomal system
under oxidative conditions. 相似文献
4.
Wood formation in poplar: identification, characterization, and seasonal variation of xylem proteins 总被引:9,自引:0,他引:9
Proteins that are preferentially produced in developing xylem may play a substantial role in xylogenesis. To reveal the identity
of these proteins, comparative two-dimensional polyacrylamide gel electrophoresis was performed on young differentiating xylem,
mature xylem, and bark of poplar (Populus trichocarpa Hook. cv. `Trichobel') harvested at different times of the year. The most-abundant xylem proteins were identified by microsequence
analysis. For 17 of these proteins a putative function could be assigned based on similarity with previously characterized
proteins, and for 15 out of these corresponding expressed sequence tags (ESTs) were found in the poplar EST database. The
identified xylem–preferential proteins, defined by comparing the protein patterns from xylem and bark, were all involved in
the phenylpropanoid pathway: two caffeoyl-coenzyme A O-methyltransferases (CCoAOMT), one phenylcoumaran benzylic ether reductase (PCBER), one bispecific caffeic acid/5-hydroxyferulic
acid O-methyltransferase (COMT), five S-adenosyl-L-methionine synthetases, and one homologue of glycine hydroxymethyltransferase (GHMT). Remarkably, the biological function
of the two most-abundant xylem-preferential proteins (PCBER and a GHMT homologue) remains unclear. In addition, several housekeeping
enzymes were identified: two enolases, two glutamine synthetases, one 70-kDa heat-shock cognate, one calreticulin, and one
α-tubulin. In comparison to the xylem-preferential proteins, the housekeeping proteins were expressed at significant levels
in the bark as well. Also, several additional protein spots were detected for CCoAOMT, PCBER, and COMT by immunoblot. Our
data show that for the study of xylogenesis, two-dimensional protein gel comparisons combined with systematic protein sequencing
may yield information complementary to that from EST sequencing strategies.
Received: 28 June 1999 / Accepted: 3 September 1999 相似文献
5.
Protein-bound advanced glycation endproducts (AGEs) as bioactive amino acid derivatives in foods 总被引:2,自引:0,他引:2
Henle T 《Amino acids》2005,29(4):313-322
Summary. The Maillard reaction or nonenzymatic browning is of outstanding importance for the formation of flavour and colour of heated
foods. Corresponding reactions, also referred to as “glycation”, are known from biological systems, where the formation of
advanced glycation endproducts (AGEs) shall play an important pathophysiological role in diabetes and uremia. In this review,
pathways leading to the formation of individual protein-bound lysine and arginine derivatives in foods are described and nutritional
consequences resulting from this posttranslational modifications of food proteins are discussed. 相似文献
6.
Fruit-specific lectins from banana and plantain 总被引:6,自引:0,他引:6
Peumans WJ Zhang W Barre A Houlès Astoul C Balint-Kurti PJ Rovira P Rougé P May GD Van Leuven F Truffa-Bachi P Van Damme EJ 《Planta》2000,211(4):546-554
One of the predominant proteins in the pulp of ripe bananas (Musa acuminata L.) and plantains (Musa spp.) has been identified as a lectin. The banana and plantain agglutinins (called BanLec and PlanLec, respectively) were
purified in reasonable quantities using a novel isolation procedure, which prevented adsorption of the lectins onto insoluble
endogenous polysaccharides. Both BanLec and PlanLec are dimeric proteins composed of two identical subunits of 15 kDa. They
readily agglutinate rabbit erythrocytes and exhibit specificity towards mannose. Molecular cloning revealed that BanLec has
sequence similarity to previously described lectins of the family of jacalin-related lectins, and according to molecular modelling
studies has the same overall fold and three-dimensional structure. The identification of BanLec and PlanLec demonstrates the
occurrence of jacalin-related lectins in monocot species, suggesting that these lectins are more widespread among higher plants
than is actually believed. The banana and plantain lectins are also the first documented examples of jacalin-related lectins,
which are abundantly present in the pulp of mature fruits but are apparently absent from other tissues. However, after treatment
of intact plants with methyl jasmonate, BanLec is also clearly induced in leaves. The banana lectin is a powerful murine T-cell
mitogen. The relevance of the mitogenicity of the banana lectin is discussed in terms of both the physiological role of the
lectin and the impact on food safety.
Received: 1 December 1999 / Accepted: 31 January 2000 相似文献
7.
8.
Wan C La Y Zhu H Yang Y Jiang L Chen Y Feng G Li H Sang H Hao X Zhang G He L 《Amino acids》2007,32(1):101-108
Summary. In this study we focused on detecting schizophrenia related changes of plasma proteins using proteomic technology and examining
the relation between schizophrenia and haptoglobin (Hp) genotype. We investigated plasma proteins from schizophrenic subjects (n = 42) and healthy controls (n = 46) by two-dimensional gel electrophoresis (2-DE) in combination with mass spectrometry. To further reveal the genetic
relationship between acute phase proteins (APPs) and schizophrenia disease, we tested Hp α1/Hp α2 (Hp 1/2) polymorphism and two single nucleotide polymorphisms (SNPs) of Hp, rs2070937 and rs5473, for associations with schizophrenia in the Chinese Han population. With the relatively high number
of samples for 2-DE work, we found that four proteins in the family of positive APPs were all up-regulated in patients. In
genetic association study, we found significant associations existing between schizophrenia and Hp polymorphisms, Hp 1/2 and rs2070937 variants. Schizophrenia is accompanied by both an altered expression of Hp protein and a different genotype
distribution of Hp gene, demonstrating that Hp is associated with schizophrenia. The results from proteomic and genomic aspects both indicate
that acute phase reaction is likely to be an aetiological agent in the pathophysiology of schizophrenia, but not just an accompanying
symptom. The positive APPs are schizophrenic related proteins, with the highly concordant results on four positive APPs.
The first two authors contributed equally. 相似文献
9.
Most proteins involved in plastid biogenesis are encoded by the nuclear genome. They are synthesised in the cytosol and have
to be transported toward and subsequently translocated into the organelle. This targeting and import process is initiated
by a specific chloroplast-targeting signal. The targeting signal of the preprotein is recognised and modified by cytosolic
proteins which function in transport toward the chloroplast and in maintaining the import-competent state of the preprotein.
The precursor is transferred onto a multi-component complex in the outer envelope of the chloroplasts, which is formed by
receptor proteins and the translocation channel. Some proteins, not containing transit sequences, are directly sorted into
the outer membrane whereas the majority, containing transit sequences, will be translocated into the stroma. This involves
the joint action of a protein complex in the outer envelope, one complex in the inner envelope, and soluble proteins in the
intermembrane space and the stroma. The origin of this translocation complex following the endosymbiotic events is an unsolved
question. Recent identification of homologous proteins to some members of this machinery in the cyanobacterium Synechocystis PCC6803 gives an initial insight into the origin of the translocation complex.
Received: 27 December 1999 / Accepted: 29 March 2000 相似文献
10.
Kahana C 《Amino acids》2007,33(2):225-230
Summary. Protein degradation mediated by the ubiquitin/proteasome system is the major route for the degradation of cellular proteins.
In this pathway the ubiquitination of the target proteins is manifested via the concerted action of several enzymes. The ubiquinated
proteins are then recognized and degraded by the 26S proteasome. There are few reports of proteins degraded by the 26S protesome
without ubiquitination, with ornithine decarboxylase being the most notable representative of this group. Interestingly, while
the degradation of ODC is independent of ubiquitination, the degradation of other enzymes of the polyamine biosynthesis pathway
is ubiquitin dependent. The present review describes the degradation of enzymes and regulators of the polyamine biosynthesis
pathway. 相似文献
11.
Amino acid analysis by hydrophilic interaction chromatography coupled on-line to electrospray ionization mass spectrometry 总被引:1,自引:0,他引:1
Summary. Collagens form a common family of triple-helical proteins classified in 21 types. This unique structure is further stabilized
by specific hydroxylation of distinct lysyl and prolyl residues forming 5-hydroxylysine and hydroxyproline (Hyp) isomers,
mostly 4-trans and 3-trans-Hyp. The molecular distribution of the Hyp-isomers among the different collagen types is still
not well investigated, even though disturbances in the hydroxylation of collagens are likely to be involved in several diseases
such as osteoporosis and autoimmune diseases. Here, a new approach to analyze underivatized amino acids by hydrophilic interaction
chromatography (HILIC) coupled on-line to electrospray ionization mass spectrometry (ESI-MS) is reported. This method can
separate all three studied Hyp-isomers, Ile, and Leu, which are all isobaric, allowing a direct qualitative and quantitative
analysis of collagen hydrolysates. The sensitivity and specificity was increased by a neutral loss scan based on the loss
of formic acid (46 u). 相似文献
12.
13.
Summary. Transmembrane (TM) proteins represent about 20–30% of the protein sequences in higher eukaryotes, playing important roles
across a range of cellular functions. Moreover, knowledge about topology of these proteins often provides crucial hints toward
their function. Due to the difficulties in experimental structure determinations of TM protein, theoretical prediction methods
are highly preferred in identifying the topology of newly found ones according to their primary sequences, useful in both
basic research and drug discovery. In this paper, based on the concept of pseudo amino acid composition (PseAA) that can incorporate
sequence-order information of a protein sequence so as to remarkably enhance the power of discrete models (Chou, K. C., Proteins:
Structure, Function, and Genetics, 2001, 43: 246–255), cellular automata and Lempel-Ziv complexity are introduced to predict
the TM regions of integral membrane proteins including both α-helical and β-barrel membrane proteins, validated by jackknife
test. The result thus obtained is quite promising, which indicates that the current approach might be a quite potential high
throughput tool in the post-genomic era. The source code and dataset are available for academic users at liml@scu.edu.cn.
Authors’ address: Menglong Li, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, P.R. China 相似文献
14.
Structural properties of proteins specific to the myelin sheath 总被引:1,自引:0,他引:1
Kursula P 《Amino acids》2008,34(2):175-185
Summary. The myelin sheath is an insulating membrane layer surrounding myelinated axons in vertebrates, which is formed when the plasma
membrane of an oligodendrocyte or a Schwann cell wraps itself around the axon. A large fraction of the total protein in this
membrane layer is comprised of only a small number of individual proteins, which have certain intriguing structural properties.
The myelin proteins are implicated in a number of neurological diseases, including, for example, autoimmune diseases and peripheral
neuropathies. In this review, the structural properties of a number of myelin-specific proteins are described.
Author’s address: Dr. Petri Kursula, Department of Biochemistry, University of Oulu, FIN-90014 Oulu, Finland 相似文献
15.
Aberrant expression of cytoskeleton proteins in hippocampus from patients with mesial temporal lobe epilepsy 总被引:8,自引:0,他引:8
Summary. Mesial temporal lobe epilepsy (MTLE), the most common form of epilepsy, is characterised by cytoarchitectural abnormalities
including neuronal cell loss and reactive gliosis in hippocampus. Determination of aberrant cytoskeleton protein expression
by proteomics techniques may help to understand pathomechanism that is still elusive. We searched for differential expression
of hippocampal proteins by an analytical method based on two-dimensional gel electrophoresis (2-DE) coupled with mass spectrometry
unambiguously identifying 77 proteins analysed in eight control and eight MTLE hippocampi. Proteins were quantified and we
observed 18 proteins that were altered in MTLE. Cytoskeleton proteins tubulin α-1 chain, β-tubulin, profilin II, neuronal
tropomodulin were significantly reduced and one actin spot was missing, whereas ezrin and vinculin were significantly increased
in MTLE. Proteins of several classes as e.g. antioxidant proteins (peroxiredoxins 3 and 6), chaperons (T-complex protein 1-α,
stress-induced-phosphoprotein 1), signaling protein MAP kinase kinase 1, synaptosomal proteins (synaptotagmin I, α-synuclein),
NAD-dependent deacetylase sirtuin-2 and 26S protease regulatory subunit 7 protein, neuronal-specific septin 3 were altered
in MTLE. Taken together, the findings may represent or lead to cytoskeletal impairment; aberrant antioxidant proteins, chaperons,
MAP kinase kinase 1 and NAD-dependent deacetylase sirtuin-2 may have been involved in pathogenetic mechanisms and altered
synaptosomal protein expression possibly reflects synaptic impairment in MTLE.
J. W. Yang and T. Czech have equally contributed to the paper. 相似文献
16.
Amino acids are building blocks of proteins, while aminoacyl-tRNA synthetases (aaRSs) catalyze the first reaction in such building: the biosynthesis of proteins. The E. coli arginyl-tRNA synthetase (ArgRS) has been crystallized in complex form with tRNA(Arg) (B. stearothermophilus), at pH 5.6 using ammonium sulfate as a precipitating agent. Two crystal forms have been identified based on unit cell dimension. The complete data sets from both crystal forms have been collected with a primitive hexagonal space group. A data set of Form II crystals at 3.2 A and 94% completeness has been obtained, with unit cell parameters a = b = 98.0 A, c = 463.2 A, and alpha = beta = 90 degrees , gamma = 120 degrees , being different from a = b = 110.8 A, c = 377.8 A for form I. The structure determination will demonstrate the interaction of these two macromolecules to understand the special mechanism of ArgRS that requires the presence of tRNA for amino acid activation. Such complex structure also provides a wide opening for inhibitor search using bioinformatics. 相似文献
17.
Summary. To date, the majority of therapeutic peptides and proteins have to be administered via parenteral routes, which are painful
and inconvenient. In order to gain sufficient high blood concentrations after oral application, various barriers in the gastrointestinal
tract have to be overcome. Apart from a poor membrane uptake and intense enzymatic degradation, this study will demonstrate
that thiol–disulphide reactions are an underestimated essential part of the presystemic metabolism. Glutathione, integrative
part of the antioxidant defence system in the gastrointestinal tract, may play an important role in the inactivation of orally
given peptides and proteins. In order to verify this hypothesis, desmopressin which bears a single disulphide bond was used
as model peptide drug. Desmopressin was incubated with GSH in various concentrations, and the extent of thiol/disulphide exchange
reactions between the peptide drug and GSH was investigated in dependence on pH and ratio of reactants determined as a function
of time via HPLC, LC-MS and Maldi-Tof-MS analyses.
Results showed that desmopressin is degraded by 1% reduced glutathione at pH 4 and pH 5.5. In presence of 0.01%, 0.1% and
1% of reduced glutathione 6.1%, 19.4% and 52.1% of desmopressin, respectively, were degraded. The masses of the conjugates
after deconvolution measured by liquid chromatography and electrospray ionisation mass spectrometric detection were m/z 1069.67, m/z 1376.50, m/z 1683.40 and m/z 2138. These molecular masses, confirmed by Maldi-Tof-MS analysis, correspond with the masses of conjugates expected in theory.
Under defined conditions, these results reveal that thiol–disulphide exchange reactions have a considerable impact on the
alteration of peptide drugs and proteins. 相似文献
18.
The flagella of the green alga Scherffelia dubia are covered by scales which consist of acidic polysaccharides and glycoproteins. Experimental deflagellation results in the
regeneration of flagella complete with scales. During flagellar regeneration, scales are newly synthesized in the Golgi apparatus,
exocytosed and deposited on the growing flagella. Flagellar regeneration is dependent upon protein synthesis and N-glycosylation,
as it is blocked by cycloheximide and partially inhibited by tunicamycin. Metabolic labeling with [35S]methionine/cysteine demonstrated that scale-associated proteins were not newly synthesized during flagellar regeneration,
suggesting that the proteins deposited on regenerating flagella were drawn from a pool. Quantitative immunoelectron microscopy
using a monospecific antibody directed against a scale-associated protein of 126 kDa (SAP126) revealed that the pool of SAP126
was primarily located at the plasma membrane, with minor labeling of the scale reticulum and trans-Golgi cisternae, both before deflagellation and during flagellar regeneration. Since SAP126 was sequestered during flagellar
regeneration into secretory vesicles together with newly synthesized scales, it is concluded that the persistent presence
of SAP126 in the trans-Golgi cisternae during scale biogenesis requires retrograde transport of the protein from the plasma membrane to the Golgi
apparatus.
Received: 3 July 1999 / Accepted: 21 August 1999 相似文献
19.
Chaves P Correa-Fiz F Melgarejo E Urdiales JL Medina MA Sánchez-Jiménez F 《Amino acids》2007,33(2):315-322
Summary. Cationic amino acids are the precursors of biogenic amines, histamine from histidine, and putrescine, spermidine and spermine
from arginine/ornithine (and methionine), as well as nitric oxide. These amines play important biological roles in inter-
and intracellular signaling mechanisms related to inflammation, cell proliferation and neurotransmission. Biochemical and
epidemiological relationships between arginine-derived products and histamine have been reported to play important roles in
physiopathological problems. In this communication, we describe the construction of an expression macroarray containing more
than 30 human probes for most of the key proteins involved in biogenic amines metabolisms, as well as other inflammation-
and proliferation-related probes. The array has been validated on human mast HMC-1 cells. On this model, we have got further
support for an inverse correlation between polyamine and histamine synthesis previously observed on murine basophilic models.
These tools should also be helpful to understand the amine roles in many other inflammatory and neoplastic pathologies.
The first two authors contributed equally to this work. 相似文献
20.