The Protein Journal (PROTEIN J)

Publisher: Springer Verlag

Journal description

The Protein Journal (formerly the Journal of Protein Chemistry) publishes original research work on all aspects of protein investigations. These include studies concerned with the structure (covalent or three-dimensional), assembly, genetics, evolution, proteomics, molecular biology, engineering, peptide synthesis or the application of these studies to the elucidation and interpretation of the molecular bases of the biological activity of proteins. All facets of protein biological functions and interactions are appropriate.

Current impact factor: 0.91

Impact Factor Rankings

2016 Impact Factor Available summer 2017
2014 / 2015 Impact Factor 0.912
2013 Impact Factor 1.039
2012 Impact Factor 1.126
2011 Impact Factor 1.038
2010 Impact Factor 1.101
2009 Impact Factor 1.017
2008 Impact Factor 0.94
2007 Impact Factor 1.01
2006 Impact Factor 0.962
2005 Impact Factor 1.2
2004 Impact Factor

Impact factor over time

Impact factor

Additional details

5-year impact 1.06
Cited half-life 4.90
Immediacy index 0.18
Eigenfactor 0.00
Article influence 0.29
Website Protein Journal, The website
Other titles Protein journal (Online)
ISSN 1572-3887
OCLC 54453099
Material type Document, Periodical, Internet resource
Document type Internet Resource, Computer File, Journal / Magazine / Newspaper

Publisher details

Springer Verlag

  • Pre-print
    • Author can archive a pre-print version
  • Post-print
    • Author can archive a post-print version
  • Conditions
    • Author's pre-print on pre-print servers such as
    • Author's post-print on author's personal website immediately
    • Author's post-print on any open access repository after 12 months after publication
    • Publisher's version/PDF cannot be used
    • Published source must be acknowledged
    • Must link to publisher version
    • Set phrase to accompany link to published version (see policy)
    • Articles in some journals can be made Open Access on payment of additional charge
  • Classification

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: Xenopus laevis endure substantial dehydration which can impose hypoxic stress due to impaired blood flow. Tissues may increase reliance on anaerobic glycolysis for energy production making the regulation of hexokinase (HK) important. We investigated the enzymatic properties and phosphorylation state of purified HK from the muscle of control and dehydrated (30 % total body water lost) frogs. Bioinformatic tools were also applied to analyze the structural implication of HK phosphorylation in silico. HK from the muscle of dehydrated frogs showed a significantly higher Vmax (3.4-fold) and Km for glucose (2.4-fold) compared with control HK but the Km for ATP was unaltered. HK from dehydrated frogs also showed greater phosphoserine content (20 % increase) and lower phosphothreonine (22 % decrease) content compared to control HK. Control HK had a higher melting temperature (Tm = 61.9 °C) than from dehydrated (Tm = 54.2 °C) frogs when thermostability was tested using differential scanning fluorimetry. In silico phosphorylation of a Xenopus HK caused alterations in active site binding, corroborating phosphorylation as the probable mechanism for kinetic regulation. Physiological consequences of dehydration-induced HK phosphorylation appear to facilitate glycolytic metabolism in hypoxic situations. Augmented HK function increases the ability of Xenopus to overcome compromised oxidative phosphorylation associated with ischemia during dehydration.
    No preview · Article · Jan 2016 · The Protein Journal
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    ABSTRACT: In order to identify the functional domains which regulate the interaction between the self-incompatibility proteins armadillo repeat containing 1 (ARC1) and exocyst 70 A1 (Exo70A1) in Brassica oleracea, fragments containing selected motifs of ARC1 (ARC1210, ARC1246, ARC1279, ARC1354) and site-specific mutants with substitutions at possible interaction sites (ARC1354m, ARC1664m) were PCR amplified and inserted into pGADT7, while coding sequences from Exo70A1 (Exo70A185, Exo70A1) were subcloned into pGBKT7. The interactions between the protein products produced by these constructs were then analyzed utilizing a yeast two-hybrid system. Our data indicate that both ARC1210 and ARC1246 interact strongly with Exo70A185 and Exo70A1, while ARC1279, ARC1354, ARC1354m and ARC1664m exhibited a weak interaction, indicating that the recognition sites are located within the 210 N-terminal amino acids of ARC1 and the 85 N-terminal amino acids of Exo70A1. This was further verified by GST pull-down analysis. This supports a model in which the N-terminal leucine zipper of ARC1 and the first 85 N-terminal amino acids of Exo70A1 mediate the interaction between these two proteins. Bioinformatic and phylogenetic analysis demonstrated that these motifs were highly conserved across different species, indicating that the interaction characterized in B. oleracea may operate in a wide array of cultivars.
    No preview · Article · Dec 2015 · The Protein Journal
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    ABSTRACT: The proteasome is the main intracellular proteolytic machine involved in the regulation of numerous cellular processes, including gene expression. In addition to their proteolytic activity, proteasomes also exhibit ATPase/helicase (the 19S particle) and RNAse (the 20S particle) activities, which are regulated by post-translational modifications. In this report we uncovered that several 20S particle subunits: α1 (PSMA6), α2 (PSMA2), α4 (PSMA7), α5 (PSMA5), α6 (PSMA1) and α7 (PSMA3) possess RNAse activity against the p53 mRNA in vitro. Furthermore, we found that the RNAse activity of PSMA1 and PSMA3 was regulated upon hemin-induced differentiation of K562 proerythroleukemia cells. The decrease in RNAse activity of PSMA1 and PSMA3 was paralleled by changes in their status of phosphorylation and ubiquitylation. Collectively, our data support the notion that proteasomal RNAse activity may be functionally important and provide insights into the potential mechanism of p53 repression in erythroleukemia cells by RNAse activity of the 20S α-type subunits.
    No preview · Article · Dec 2015 · The Protein Journal
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    ABSTRACT: Laccases, which belong to the blue copper oxidase enzyme family, oxidize many organic and inorganic compounds. The laccase-encoding genes DcLac1 and DcLac2 were isolated from the economically important tuberous root carrot, and their proteins were successfully expressed and purified using the Escherichia coli expression system BL21(DE3). DcLac1 and DcLac2 had molecular masses of approximately 64 and 61.9 kDa, respectively. With 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulfonate acid) as the substrate, DcLac1 and DcLac2 had K m values of 3.9043 and 1.255 mM, respectively, and V max values of 54.0832 and 81.7996 μM mg−1 min−1, respectively. Moreover, DcLac1 and DcLac2 had optimal pH values of 2.8 and 2.6, respectively, and optimal temperatures of 45 and 40 °C, respectively. The activities of the two enzymes were promoted by Ca2+, Mg2+, Cu2+, and Na+ but inhibited by Fe2+, Zn2+, Mn2+, K+, SDS, and EDTA. Expression profiles showed that the two DcLac genes had almost identical responses to high and low temperature stresses but different responses to salt, drought, and metal stresses. This study provided insights into the characteristics and tolerance response mechanisms of laccase in carrot.
    No preview · Article · Dec 2015 · The Protein Journal
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    ABSTRACT: Hypericin is a photosensitizer compound used in the photodynamic therapy (PDT). PDT is an alternative cancer treatment strategy whose function is dependent on the photosensitizers accumulating selectively in tumor cells and following visible or infra-red light induced activation lead to the apoptosis/necrosis of the tumor cells via the formation of reactive oxygen species. Thus, the cellular redox balance is essential for the efficacy of PDT. Among the protective enzyme systems glutathione S-transferases (GST, E.C. function in detoxification, protection against oxidative stress and intracellular transport of molecules. It is known that isoenzymes of GST and especially GST-pi is increased in cancer cells and it plays very important functions in the development of resistance to anticancer drugs. Since photosensitizers are used intravenously, it is important to elucidate the effects of photosensitizers on the erythrocyte enzymes. The aim of the present study was to investigate the impact of hypericin on human erythrocyte GST-pi (heGST-pi). Purification yield of 71 % and purification fold of 2550 were achieved by using conventional chromatographic methods. The specific activity of the enzyme is found as 51 U/mg protein. Hypericin inhibited heGST-pi in a dose dependent manner and inhibition was biphasic. Noncompetitive type of inhibition was observed with both substrates, GSH and CDNB. The inhibitory constant (K i ) values obtained from Lineweaver–Burk, Dixon, secondary plots; slope and y-intercept versus 1/S (substrate) and from non-linear regression analysis were in good correlation: K i (GSH) was calculated as 0.19 ± 0.01 μM and K i (CDNB) as 0.26 ± 0.03 μM.
    No preview · Article · Nov 2015 · The Protein Journal
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    ABSTRACT: Myo-inositol-1-phosphate synthase (MIPS, E.C. catalyzes the first step in inositol production—the conversion of glucose-6-phosphate (Glc-6P) to myo-inositol-1-phosphate. While the three dimensional structure of MIPS from Mycobacterium tuberculosis has been solved, biochemical studies examining the in vitro activity have not been reported to date. Herein we report the in vitro activity of mycobacterial MIPS expressed in E. coli and Mycobacterium smegmatis. Recombinant expression in E. coli yields a soluble protein capable of binding the NAD+ cofactor; however, it has no significant activity with the Glc-6P substrate. In contrast, recombinant expression in M. smegmatis mc24517 yields a functionally active protein. Examination of structural data suggests that MtMIPS expressed in E. coli adopts a fold that is missing a key helix containing two critical (conserved) Lys side chains, which likely explains the inability of the E. coli expressed protein to bind and turnover the Glc-6P substrate. Recombinant expression in M. smegmatis may yield a protein that adopts a fold in which this key helix is formed enabling proper positioning of important side chains, thereby allowing for Glc-6P substrate binding and turnover. Detailed mechanistic studies may be feasible following optimization of the recombinant MIPS expression protocol in M. smegmatis.
    No preview · Article · Sep 2015 · The Protein Journal
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    ABSTRACT: Glucose-6-phosphate dehydrogenase (G6PD) is a key regulatory enzyme involved in the pentose phosphate pathway. This works represents purification of two buffalo liver glucose-6-phosphate dehydrogenases (BLG6PD1 and BLG6PD2) using combination of ammonium sulfate precipitation and several chromatographic columns. Both enzymes (BLG6PD1 and BLG6PD2) were homogenous on both native PAGE as well as 12 % SDS PAGE with molecular weights of 28 and 66 kDa. The molecular weight of BLG6PD1 and BLG6PD2 native forms were determined to be 28 and 66 kDa by gel filtration; indicating monomeric proteins. The K m values for BLG6PD1 and BLG6PD2 estimated to be 0.059 and 0.06 mM of β-nicotinamide adenine dinucleotide phosphate. The optimum activity of BLG6PD1 and BLG6PD2 were displayed at pH 8.0 and 8.2 with an isoelectric point (pI) of pH 7.7-7.9 and 5.7-5.9. The divalent cations MgCl2, and CoCl2 act as activators, on the other hand, FeCl2, CuCl2 and ZnCl2 are potent inhibitors of BLG6PD1 and BLG6PD2 activity. NADPH inhibited both isoenzymes competitively with Ki values of 0.012 and 0.030 mM. This study describes a reproducible purification scheme of G6PD from the liver of buffalo as a rich source.
    No preview · Article · May 2015 · The Protein Journal
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    ABSTRACT: Previously we purified fibrinogenase from venom of Echis multisquamatis and showed that the enzyme predominantly cleaves BβArg42-Ala43 peptide bond of fibrinogen. A much slower hydrolysis of its Aα-chain was also shown. To evaluate the accessibility of the hydrolysis sites to fibrinogenase's hydrolytic action, the pathway of cleavage of Aα- and Bβ-chains of fibrinogen, monomeric and polymeric fibrin desA and desAB has been investigated using western blot with monoclonal antibodies to Bβ 26-42 and Aα 20-78 of fibrinogen. The data indicated that the BβArg42-Ala43 peptide bond is available for cleavage in all forms of fibrin(ogen) with the exception of polymerized fibrin desAB. This is direct evidence of BβN-domain involvement in formation of protofibrils that makes it inaccessible to protease. The Aα-chain of fibrinogen remained intact after 3 min of incubation with fibrinogenase. Further incubation resulted in cleaving of the fibrin(ogen) αC-regions with the formation of two kinds of degradation products (~30 and ~60 kDa). In the case of monomeric fibrin desA or desAB we observed simultaneous hydrolysis of Aα and Bβ-chains and the cleavage of Aα-chain was more apparent for both forms of polymeric fibrin.
    No preview · Article · Mar 2015 · The Protein Journal
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    ABSTRACT: Directed evolution is a common tool employed to generate enzymes suitable for industrial use. High thermal stability is often advantageous or even a requirement for biocatalysts, as such the evolution of protein stability is of practical as well as academic interest. Even when evolving enzymes for new or improved catalytic functions, stability is an important factor since it can limit the accumulation rate and number of desired active site mutations. Dienelactone hydrolase, a small monomeric protein, has been previously evolved via a three-stage process to possess enhanced activity and specificity toward non-physiological substrates. In addition to seven active site mutations there were three surface mutations that were thought to increase the stability of the enzyme and compensate for the destabilizing active site mutations. Here, the individual influence of the three surface mutations-Q110L, Y137C and N154D-on the thermal and chemical stability of DLH has been assessed. While the Q110L and N154D mutations improved the thermal stability, the influence of the Y137C mutation was more complex. Individually it was destabilizing both thermally and chemically, but when in the presence of the Q110L and N154D mutations its effect was neutralized in relation to thermal but not chemical stability. In the context of a directed evolution experiment, these compensatory surface mutations play important roles. However, our results show that detrimental mutations can arise, thus the simultaneous monitoring of stability changes while evolving enzymes for enhanced catalytic properties can be beneficial.
    Preview · Article · Feb 2015 · The Protein Journal