A Novel Method for the Purification of Selenoprotein P from Human Plasma

doi:10.1006/abbi.1998.0809

Archives of Biochemistry and Biophysics

Volume 357, Issue 2, 15 September 1998, Pages 326-330

https://doi.org/10.1006/abbi.1998.0809 Get rights and content

Abstract

Selenoprotein P was purified from human plasma using conventional chromatographic methods featuring metal-chelate-affinity chromatography as the final step. Two distinct isoforms with different selenium content were isolated and identified by N-terminal sequencing and immunoblot analysis. Their molecular mass is 61 and 51 kDa, respectively. Both isoforms could be detected in fresh plasma from five individuals. This rules out the possibility of the second isoform being an artifact which results from degradation of full-length selenoprotein P during purification.

References (28)

L. Flohé et al.
FEBS Lett.
(1973)
F. Ursini et al.
Biochim. Biophys. Acta
(1985)
K. Takahashi et al.
Arch. Biochem. Biophys.
(1987)
F.F. Chu et al.
J. Biol. Chem.
(1993)
D. Behne et al.
Biochem. Biophys. Res. Commun.
(1990)
W. Croteau et al.
J. Biol. Chem.
(1995)
J.L. Herrman
Biochim. Biophys. Acta
(1977)
J.G. Yang et al.
J. Biol. Chem.
(1987)
B. Åkesson et al.
Biochim. Biophys. Acta
(1994)
R.F. Burk et al.
Hepatology
(1995)

B. Eberle et al.

J. Trace Elements Med. Biol.

(1995)

J. Kyte et al.

J. Mol. Biol.

(1982)

M.M. Bradford

Anal. Biochem.

(1976)

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The effect of acute and chronic inflammatory response on plasma and erythrocyte selenium concentrations: Implications for assessing selenium nutritional status
2024, Clinical Nutrition Open Science
Selenium is an essential trace element and its deficiency can lead to dysfunction in multiple areas. Selenium status is commonly assessed by its measurement in plasma but this may be an unreliable marker in patients with systemic inflammatory response (SIR). Erythrocyte selenium is an alternative marker that appears not to be perturbed by the SIR.
Examine the effect of the magnitude of acute and chronic SIR on plasma and erythrocyte selenium concentrations.
Acute inflammation: Blood samples were collected in patients (n=16) undergoing elective knee arthroplasty pre-operatively and post-operatively (24 and 48 hours and 3 months). Chronic inflammation: Blood samples were collected in patients receiving nutritional support who presented for routine micronutrient screening (n = 3798). CRP was used as a marker of inflammation. Plasma and erythrocyte selenium concentrations were divided into 3 inflammatory groups: minor, moderate and major defined as CRP<10, 11–80, >80 mg/L.
Plasma selenium concentrations reduced with increasing CRP concentrations from minor to moderate to major inflammation (P<0.001), whereas erythrocyte selenium concentrations only reduced in chronic major inflammation. In both acute and chronic inflammation, median plasma selenium concentrations were within the local laboratory defined reference interval (0.75–1.50 μmol/L) with minor and moderate inflammation, whereas in major inflammation they were below the reference interval. In contrast, median erythrocyte selenium concentrations remained within the local laboratory defined reference interval (3.0–9.0 nmol/g haemoglobin) in the context of minor, moderate and major inflammation in both acute and chronic inflammation cohorts. Furthermore, in the chronic inflammation cohort, concordance between plasma and erythrocyte selenium concentrations at the lower limit of the reference intervals decreased from 84% of patients with minor inflammation, to 66% and 44% in patients with moderate and major inflammation respectively.
In both acute and chronic inflammation, plasma selenium concentrations fell significantly with rising CRP, whereas erythrocyte selenium concentrations were less affected.
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The Selenium Transport Protein, Selenoprotein P, Requires Coding Sequence Determinants to Promote Efficient Selenocysteine Incorporation
2018, Journal of Molecular Biology
Selenoproteins are an essential and unique group of proteins in which selenocysteine (Sec) is incorporated in response to a stop codon (UGA). Reprograming of UGA for Sec insertion in eukaryotes requires a cis-acting stem–loop structure in the 3′ untranslated region of selenoprotein mRNA and several trans-acting factors. Together these factors are sufficient for Sec incorporation in vitro, but the process is highly inefficient. An additional challenge is the synthesis of selenoprotein P (SELENOP), which uniquely contains multiple UGA codons. Full-length SELENOP expression requires processive Sec incorporation, the mechanism for which is not understood. In this study, we identify core coding region sequence determinants within the SELENOP mRNA that govern SELENOP synthesis. Using ⁷⁵Se labeling in cells, we determined that the N-terminal coding sequence (upstream of the second UGA) and C-terminal coding sequence context are two independent determinants for efficient synthesis of full-length SELENOP. In addition, the distance between the first UGA and the consensus signal peptide is also critical for efficiency.
The effect of the systemic inflammatory response on plasma zinc and selenium adjusted for albumin
2016, Clinical Nutrition
The magnitude of systemic inflammatory response, as evidenced by C-reactive protein (CRP), is a major factor associated with lower zinc and selenium. They may also be influenced by their binding proteins, such as albumin. The aim of the present study was to examine the relationships between plasma zinc, selenium and the systemic inflammatory response in a large cohort of patients referred for nutritional screen and also to examine these relationships in patients with critical illness.
Patients referred for nutritional assessment of zinc (n = 743) and selenium (n = 833) and 114 patients with critical illness were examined. Intra-assay imprecision was <10% for these analytes.
In the nutritional screen cohort, plasma zinc was significantly associated with CRP (r_s = −0.404, p < 0.001) and albumin (r_s = 0.588, p < 0.001). For each CRP category (≤10, 11–80, >80 mg/l) the zinc/albumin ratio x100 was similar (31, 33 and 32 respectively, p = 0.029). Plasma selenium was significantly associated with CRP (r_s = −0.489, p < 0.001) and albumin (r_s = 0.600, p < 0.001). With increasing CRP category (≤10, 11–80, >80 mg/l) the selenium/albumin ratio ×100 was lower (2.3, 2.1 and 1.8 respectively, p < 0.001). Similar relationships were also observed in the cohort of patients with critical illness.
Plasma zinc was associated with both CRP and albumin. The impact of the systemic inflammatory response could be largely adjusted by albumin concentrations. Plasma selenium was associated with both CRP and albumin. The impact of the systemic inflammatory response on plasma selenium concentrations could not be reasonably adjusted by albumin concentrations.
Assessment of plasma and red cell trace element concentrations, disease severity, and outcome in patients with critical illness
2014, Journal of Critical Care
Citation Excerpt :
In addition, although selenium and copper may be bound to albumin, these elements are actually integral components of SePP and ceruloplasmin, respectively. The reduction in SePP may be a result of down-regulation of synthesis by the liver as well as protein redistribution [27,28]. In the present study unlike plasma selenium and zinc concentrations, we found plasma copper concentrations remained within the reference interval at admission.
The purpose of the study is to examine the value of both plasma and red cell trace element measurements when assessing nutritional status in patients with critical illness.
A total of 125 patients who were admitted to intensive care unit with evidence of systemic inflammatory response as per Bone's criteria were recruited. Venous blood samples were obtained from all on admission and, in 31 of the 125 patients, on approximately days 4 and 7. Copper, zinc, and selenium concentrations were measured in plasma and erythrocytes and results related to mortality and patient outcome measures.
A total of 125 critically ill patients were recruited; 81 (66%) were male, the median age was 60 (range, 18-100), and the medical/surgical proportion was 55/70 (44%/56%). The median (lower and upper 2.5th percentile) Acute Physiology and Chronic Health Evaluation II score, Sequential Organ Failure Assessment score, and length of stay and mortality were 21 (16-26), 7 (4-9) 3.7 days (1.5-11.1) and 19%, respectively. Plasma zinc and selenium concentrations were significantly lower on admission compared with reference intervals, whereas copper was increased. Normal plasma glutathione peroxidase activity suggested selenium status was adequate on admission; erythrocyte concentrations of glutathione peroxidase and trace elements were normal, suggesting adequate nutritional status 1 to 2 months before admission. Only plasma zinc and selenium were inversely associated with C-reactive protein (r_s = − 0.266, P = .004, r_s = − 0.322, P < .001, respectively). Compared with survivors, albumin (P < .001) concentrations were significantly lower in the nonsurvivor group. No significant difference of plasma selenium and zinc between survivors and nonsurvivors was found, although plasma selenium concentrations tended to be lower (P = .04). On multivariate logistic regression analysis of the significant variables, none was independently associated with mortality.
The altered plasma concentrations of zinc, selenium, and copper in patients with critical illness were primarily due to the effects of the systemic inflammatory response and do not reliably indicate their status.
Genetic variants in selenoprotein P plasma 1 gene (SEPP1) are associated with fasting insulin and first phase insulin response in Hispanics
2014, Gene
Insulin resistance is not fully explained on a molecular level, though several genes and proteins have been tied to this defect. Knockdowns of the SEPP1 gene, which encodes the selenoprotein P (SeP) protein, have been shown to increase insulin sensitivity in mice. SeP is a liver-derived plasma protein and a major supplier of selenium, which is a proposed insulin mimetic and antidiabetic agent.
SEPP1 single nucleotide polymorphisms (SNPs) were selected for analysis with glucometabolic measures.
The study included1424 Hispanics from families in the Insulin Resistance Atherosclerosis Family Study (IRASFS). Additionally, the multi-ethnic Insulin Resistance Atherosclerosis Study was used. A frequently sampled intravenous glucose tolerance test was used to obtain precise measures of acute insulin response (AIR) and the insulin sensitivity index (S_I).
21 SEPP1 SNPs (tagging SNPs (n = 12) from HapMap, 4 coding variants and 6 SNPs in the promoter region) were genotyped and analyzed for association.
Two highly correlated (r² = 1) SNPs showed association with AIR (rs28919926; Cys368Arg; p = 0.0028 and rs146125471; Ile293Met; p = 0.0026) while rs16872779 (intronic) was associated with fasting insulin levels (p = 0.0097). In the smaller IRAS Hispanic cohort, few of the associations seen in the IRASFS were replicated, but meta-analysis of IRASFS and all 3 IRAS cohorts (N = 2446) supported association of rs28919926 and rs146125471 with AIR (p = 0.013 and 0.0047, respectively) as well as rs7579 with S_I (p = 0.047).
Overall, these results in a human sample are consistent with the literature suggesting a role for SEPP1 in insulin resistance.
Regulation of selenocysteine incorporation into the selenium transport protein, selenoprotein P
2014, Journal of Biological Chemistry
Selenoproteins are unique as they contain selenium in their active site in the form of the 21st amino acid selenocysteine (Sec), which is encoded by an in-frame UGA stop codon. Sec incorporation requires both cis- and trans-acting factors, which are known to be sufficient for Sec incorporation in vitro, albeit with low efficiency. However, the abundance of the naturally occurring selenoprotein that contains 10 Sec residues (SEPP1) suggests that processive and efficient Sec incorporation occurs in vivo. Here, we set out to study native SEPP1 synthesis in vitro to identify factors that regulate processivity and efficiency. Deletion analysis of the long and conserved 3′-UTR has revealed that the incorporation of multiple Sec residues is inherently processive requiring only the SECIS elements but surprisingly responsive to the selenium concentration. We provide evidence that processive Sec incorporation is linked to selenium utilization and that reconstitution of known Sec incorporation factors in a wheat germ lysate does not permit multiple Sec incorporation events, thus suggesting a role for yet unidentified mammalian-specific processes or factors. The relationship between our findings and the channeling theory of translational efficiency is discussed.

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Regular ArticleA Novel Method for the Purification of Selenoprotein P from Human Plasma

Abstract

FEBS Lett.

Biochim. Biophys. Acta

Arch. Biochem. Biophys.

J. Biol. Chem.

Biochem. Biophys. Res. Commun.

J. Biol. Chem.

Biochim. Biophys. Acta

J. Biol. Chem.

Biochim. Biophys. Acta

Hepatology

J. Trace Elements Med. Biol.

J. Mol. Biol.

Anal. Biochem.

Regular Article
A Novel Method for the Purification of Selenoprotein P from Human Plasma