Identification Of Apolipoprotein Research Articles

New plasma LC-MS/MS assays for the quantitation of beta-amyloid peptides and identification of apolipoprotein E proteoforms for Alzheimer's disease risk assessment.

Early detection of Alzheimer's disease (AD) represents an unmet clinical need. Beta-amyloid (Aβ) plays an important role in AD pathology, and the Aβ42/40 peptide ratio is a good indicator for amyloid deposition. In addition, variants of the apolipoprotein E (APOE) gene are associated with variable AD risk. Here, we describe the development and validation of high-throughput liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays for plasma Aβ40 and Aβ42 quantitation, as well as apolipoprotein E (ApoE) proteotype determination as a surrogate for APOE genotype. Aβ40 and Aβ42 were simultaneously immunoprecipitated from plasma, proteolytically digested, and quantitated by LC-MS/MS. ApoE proteotype status was qualitatively assessed by targeting tryptic peptides from the ApoE2, ApoE3, and ApoE4 proteoforms. Both assays were validated according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Within-run precision was 1.8%-4.2% (Aβ40), 1.9%-7.2% (Aβ42), and 2.6%-8.3% (Aβ42/40 ratio). Between-run precision was 3.5%-5.9% (Aβ40), 3.8%-8.0% (Aβ42), and 3.3%-8.7% (Aβ42/40 ratio). Both Aβ40 and Aβ42 were linear from 10 to 2500 pg/mL. Identified ApoE proteotypes had 100% concordance with APOE genotypes. We have developed a precise, accurate, and sensitive high-throughput LC-MS/MS assay for plasma Aβ40, Aβ42, and proteoforms of ApoE.

Identification of apolipoprotein A-I as a target of platelet tyrosine kinases

Identification of apolipoprotein A-I as a target of platelet tyrosine kinases

Identification of Apolipoprotein D as a Dermal Fibroblast Marker of Human Aging for Development of Skin Rejuvenation Therapy.

The current understanding of skin aging is that senescent fibroblasts accumulate within the dermis and subcutaneous fat to cause abnormal tissue remodeling and extracellular matrix dysfunction, triggering a senescence-associated secretory phenotype (SASP). A novel therapeutic approach to prevent skin aging is to specifically eliminate senescent dermal fibroblasts; this requires the identification of specific protein markers for senescent cells. Apolipoprotein D (ApoD) is involved in lipid metabolism and antioxidant responses and is abundantly expressed in tissues affected by age-related diseases such as Alzheimer's disease and atherosclerosis. However, its behavior and role in skin aging remain unclear. In this study, we examined whether ApoD functions as a marker of aging using human dermal fibroblast aging models. In cellular senescence models induced through replicative aging and ionizing radiation exposure, ApoD expression was upregulated at the gene and protein levels and correlated with senescence-associated β-galactosidase activity and the decreased uptake of the proliferation marker bromodeoxyuridine, which was concomitant with the upregulation of SASP genes. Furthermore, ApoD-positive cells were found to be more abundant in the aging human dermis using fluorescence flow cytometry. These results suggest that ApoD is a potential clinical marker for identifying aging dermal fibroblasts.

LDLR, VLDLR and APOBR in the pathophysiology of sporadic Alzheimer’s disease

AbstractBackgroundAlzheimer’s disease (AD) and cholesterol homeostasis have long been linked, most notably by the identification of apolipoprotein E‐ε4 allele as the strongest risk factor. Yet the mechanism by which its pathogenic isoform ε4 impacts AD has remained elusive. Different GWA studies have identified other potential risk factors, many of which are also involved in the maintenance, homeostasis, mobilisation, and distribution of cholesterol. The aim of this study was to analyse three candidate genes involved in cholesterol metabolism, which showed preliminary significance and are strongly related to cholesterol processes and APOE neurobiology.MethodThe three candidates are the receptors LDLR, VLDLR and APOBR which were analysed using neocortical mRNA data from the Religious Orders study/ Memory and Aging Project ROSMAP cohort’s dataset. The receptor mRNA levels were contrasted against several AD pathological markers, such as Braak and CERAD stages. Other apolipoprotein mRNA levels were also analysed for significance. Age, Sex and ApoE4 genotype were also tested for effect.ResultPreliminary analyses showed significant correlation between mRNA levels of these receptors (most strongly VLDLR) and Braak stages (VLDLR p < 0.008), CERAD stages (VLDLR p < 0.001) as well as several proteins known to be involved in AD pathophysiology. VLDLR expression levels did not correlate with APOE mRNA levels (VLDLR; R2=0.176, p > 0.05) and were only significant in APOε4 negative subjects when split for APOε4 genotype (VLDLR Braak p < 0.003).ConclusionThe three receptors analysed so far appear to be involved at some level with AD pathophysiology. They will be further studied and investigated in both, symptomatic and pre‐symptomatic AD. The relationship between the receptors and APOE pathophysiology in sporadic AD remains unclear.

ApoPred: Identification of Apolipoproteins and Their Subfamilies With Multifarious Features.

Apolipoprotein is a group of plasma proteins that are associated with a variety of diseases, such as hyperlipidemia, atherosclerosis, Alzheimer’s disease, and diabetes. In order to investigate the function of apolipoproteins and to develop effective targets for related diseases, it is necessary to accurately identify and classify apolipoproteins. Although it is possible to identify apolipoproteins accurately through biochemical experiments, they are expensive and time-consuming. This work aims to establish a high-efficiency and high-accuracy prediction model for recognition of apolipoproteins and their subfamilies. We firstly constructed a high-quality benchmark dataset including 270 apolipoproteins and 535 non-apolipoproteins. Based on the dataset, pseudo-amino acid composition (PseAAC) and composition of k-spaced amino acid pairs (CKSAAP) were used as input vectors. To improve the prediction accuracy and eliminate redundant information, analysis of variance (ANOVA) was used to rank the features. And the incremental feature selection was utilized to obtain the best feature subset. Support vector machine (SVM) was proposed to construct the classification model, which could produce the accuracy of 97.27%, sensitivity of 96.30%, and specificity of 97.76% for discriminating apolipoprotein from non-apolipoprotein in 10-fold cross-validation. In addition, the same process was repeated to generate a new model for predicting apolipoprotein subfamilies. The new model could achieve an overall accuracy of 95.93% in 10-fold cross-validation. According to our proposed model, a convenient webserver called ApoPred was established, which can be freely accessed at http://tang-biolab.com/server/ApoPred/service.html. We expect that this work will contribute to apolipoprotein function research and drug development in relevant diseases.

<p>Identification of Apolipoprotein E as a Potential Diagnostic Biomarker of Nasopharyngeal Carcinoma</p>

PurposeApo-E, a secreted protein, is closely related to the migration and invasion of tumor cells. In this study, we aimed to analyze the expression of Apo-E in nasopharyngeal carcinoma (NPC) patients and cell lines, as well as its effects on NPC cell behavior.Patients and MethodsOur study included 35 patients with NPC from Zhongnan Hospital. Expression levels of Apo-E in patients with NPC were examined by quantitative reverse transcription-polymerase chain reaction, Western blot, and immunohistochemical (IHC) staining. Receiver operating characteristic (ROC) curves were analyzed using the SPSS 22 software to estimate the sensitivity and specificity of the Apo-E protein in diagnosing NPC. Additionally, the level of Apo-E in NPC cell lines (NP69, 6–10B, and 5–8F) was investigated by Western blotting and IHC.ResultsLevels of Apo-E were higher in NPC patients than in controls. Moreover, ROC analysis revealed that increased Apo-E in the serum of NPC patients may act as a potential biomarker for NPC diagnosis (Area under the curve 0.917). Furthermore, similar results were also identified in NPC cancer cell lines. RNA interference technology was used to overexpress the endogenous Apo-E in the NPC cell line 6–10B. Wound healing and transwell assays indicated that the overexpression of Apo-E increased the number of cell colonies and migration ability, respectively.ConclusionIn this study, we found that Apo-E was elevated in NPC patients and may act as a potential biomarker for NPC diagnosis. In addition, Apo-E was upregulated in NPC cell lines and promoted cell growth, migration, and invasion.

Identification of Apolipoprotein A‐IV Receptor: a Possibility of an Orphan GPCR?

Apolipoprotein‐A4 (apoA‐IV) is a 46 kDa protein that participates in many physiological functions including glucose homeostasis, lipid metabolism, and satiation. Thus, apoA‐IV could serve as a potential target candidate for the treatment of obesity, diabetes, and cardiovascular diseases. A previous study showed that apoA‐IV binds to the plasma membrane of human hepatic cells, but the membrane receptor responsible for apoA‐IV binding remains unknown. In addition, apoA‐IV exerts its physiological roles through PI3K/Akt signaling pathway in rat hypothalamus and mouse adipocytes. We therefore hypothesize that apoA‐IV interacts with a G‐protein‐coupled receptor, more specifically an orphan GPCR. To test this hypothesis, we are employing our Deductive Reasoning Strategy to match apoA‐IV with its potential receptors. Human gastric carcinoma cells (KATO III) and human liver hepatocellular carcinoma cells (HEPG2) treated with apoA‐IV exhibited significant increases in c‐FOS mRNA expression as measured by qPCR. In addition, KATO III and HEPG2 cells expressed many of the overlapping orphan GPCRs. These results suggest that an orphan GPCR for apoA‐IV ligand may potentially exist. Testing other cell lines for their responsiveness to apoA‐IV treatment and expression for orphan GPCRs as well as employing siRNA‐mediated knockdown of orphan GPCRs that are expressed by all tested cell lines is being performed to identify a potentially specific orphan GPCR that interacts with apoA‐IV. Identification of apoA‐IV receptor would provide a novel platform for apoA‐IV‐based therapeutics.Support or Funding InformationNational Institute of HealthThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Identification of Apolipoprotein A-I as a Retinoic Acid-binding Protein in the Eye

All-trans-retinoic acid may be an important molecular signal in the postnatal control of eye size. The goal of this study was to identify retinoic acid-binding proteins secreted by the choroid and sclera during visually guided ocular growth. Following photoaffinity labeling with all-trans-[11,12-(3)H]retinoic acid, the most abundant labeled protein detected in the conditioned medium of choroid or sclera had an apparent Mr of 27,000 Da. Following purification and mass spectrometry, the Mr 27,000 band was identified as apolipoprotein A-I. Affinity capture of the radioactive Mr 27,000 band by anti-chick apolipoprotein A-I antibodies confirmed its identity as apolipoprotein A-I. Photoaffinity labeling and fluorescence quenching experiments demonstrated that binding of retinoic acid to apolipoprotein A-I is 1) concentration-dependent, 2) selective for all-trans-retinoic acid, and 3) requires the presence of apolipoprotein A-I-associated lipids for retinoid binding. Expression of apolipoprotein A-I mRNA and protein synthesis were markedly up-regulated in choroids of chick eyes during the recovery from induced myopia, and apolipoprotein A-I mRNA was significantly increased in choroids following retinoic acid treatment. Together, these data suggest that apolipoprotein A-I may participate in a regulatory feedback mechanism with retinoic acid to control the action of retinoic acid on ocular targets during postnatal ocular growth.

Identification of apolipoprotein using feature selection technique.

Apolipoprotein is a kind of protein which can transport the lipids through the lymphatic and circulatory systems. The abnormal expression level of apolipoprotein always causes angiocardiopathy. Thus, correct recognition of apolipoprotein from proteomic data is very crucial to the comprehension of cardiovascular system and drug design. This study is to develop a computational model to predict apolipoproteins. In the model, the apolipoproteins and non-apolipoproteins were collected to form benchmark dataset. On the basis of the dataset, we extracted the g-gap dipeptide composition information from residue sequences to formulate protein samples. To exclude redundant information or noise, the analysis of various (ANOVA)-based feature selection technique was proposed to find out the best feature subset. The support vector machine (SVM) was selected as discrimination algorithm. Results show that 96.2% of sensitivity and 99.3% of specificity were achieved in five-fold cross-validation. These findings open new perspectives to improve apolipoproteins prediction by considering the specific dipeptides. We expect that these findings will help to improve drug development in anti-angiocardiopathy disease.

Abstract 473: Identification of Apolipoproteins Using Feature Selection Technique

Objective: Apolipoproteins are of great physiological importance and are associated with different diseases such as dyslipidemia, thrombogenesis and angiocardiopathy. Apolipoproteins have therefore emerged as key risk markers and important research targets yet the types of apolipoproteins has not been fully elucidated. Accurate identification of the apoliproproteins is very crucial to the comprehension of cardiovascular diseases and drug design. The aim of this study is to develop a powerful model to precisely identify apolipoproteins. Approach and Results: We manually collected a non-redundant dataset of 53 apoliproproteins and 136 non-apoliproproteins with the sequence identify of less than 40% from UniProt. After formulating the protein sequence samples with g -gap dipeptide composition (here g =1~10), the analysis of various (ANOVA) was adopted to find out the best feature subset which can achieve the best accuracy. Support Vector Machine (SVM) was then used to perform classification. The predictive model was evaluated using a five-fold cross-validation which yielded a sensitivity of 96.2%, a specificity of 99.3%, and an accuracy of 98.4%. The study indicated that the proposed method could be a feasible means of conducting preliminary analyses of apoliproproteins. Conclusion: We demonstrated that apoliproproteins can be predicted from their primary sequences. Also we discovered the special dipeptide distribution in apoliproproteins. These findings open new perspectives to improve apoliproproteins prediction by considering the specific dipeptides. We expect that these findings will help to improve drug development in anti-angiocardiopathy disease. Key words: Apoliproproteins Angiocardiopathy Support Vector Machine

Identification of Apolipoprotein C-I Peptides as a Potential Biomarker and its Biological Roles in Breast Cancer.

BackgroundBreast cancer (BC) is one of the most common cancers and is among the main causes of death in females around the world. Although several serum biomarkers have been identified for breast cancer, due to lack of adequate sensitivity and specificity they do not adequately distinguish BC from confounding conditions. New approaches are urgently needed to improve BC detection and treatment.Material/MethodsEighty serum samples from 20 healthy individuals and 60 patients with BC (22 triple-negative breast cancer, TNBC; 38 non-triple-negative breast cancer, NTNBC) were included. Protein profiling of serum samples was analyzed using surface-enhanced laser desorption/ionization time-of-flight mass spectroscopy (SELDI-TOF-MS). Candidate biomarkers were purified by SDS-PAGE electrophoresis and identified by MALDI-TOF/TOF.ResultsThe candidate biomarker positioned at 6447.9 m/z was significantly decreased in BC patients. Moreover, the expression intensity of the candidate biomarker was weaker in the TNBC and pre-surgery group compared with the NTNBC and post-surgery group. We ultimately identified the biomarker as apolipoprotein C-I (ApoC-I). Furthermore, we found that ApoC-I peptides inhibited proliferation of human breast cancer cells in vitro and suppressed tumor growth in vivo.ConclusionsThese results suggest that ApoC-I peptides may be a potential diagnostic biomarker and therapeutic approach for BC.

Apolipoprotein C-II Deposition Amyloidosis: A Potential Misdiagnosis as Light Chain Amyloidosis.

Hereditary amyloidoses are rare and pose a diagnostic challenge. We report a case of hereditary amyloidosis associated with apolipoprotein C-II deposition in a 61-year-old female presenting with renal failure and nephrotic syndrome misdiagnosed as light chain amyloidosis. Renal biopsy was consistent with amyloidosis on microscopy; however, immunofluorescence was inconclusive for the type of amyloid protein. Monoclonal gammopathy evaluation revealed kappa light chain. Bone marrow biopsy revealed minimal involvement with amyloidosis with kappa monotypic plasma cells on flow cytometry. She was started on chemotherapy for light chain amyloidosis. She was referred to the Mayo clinic where laser microdissection and liquid chromatography mass spectrometry detected high levels of apolipoprotein C-II, making a definitive diagnosis. Apolipoprotein C-II is a component of very low-density lipoprotein and aggregates in lipid-free conditions to form amyloid fibrils. The identification of apolipoprotein C-II as the cause of amyloidosis cannot be solely made with routine microscopy or immunofluorescence. Further evaluation of biopsy specimens with laser microdissection and mass spectrometry and DNA sequencing of exons should be done routinely in patients with amyloidoses for definitive diagnosis. Our case highlights the importance of determining the subtype of amyloidosis that is critical for avoiding unnecessary therapy such as chemotherapy.

Screening and identification of apolipoprotein A-I as a potential hepatoblastoma biomarker in children, excluding inflammatory factors.

The aim of the present study was to identify a child hepatoblastoma serum biomarker that is unaffected by inflammatory factors, with the ultimate aim of finding an effective method for the early diagnosis of hepatoblastoma. The magnetic bead-based weak cation exchange chromatography technique was used to process serum harvested from 30 children with hepatoblastoma, 20 children with systemic inflammatory response syndrome (SIRS) and 20 healthy children. Proteins differentially expressed in SIRS were excluded from consideration as biomarkers for hepatoblastoma. Proteins differentially expressed in hepatoblastoma and healthy controls were screened using surface-enhanced laser desorption/ionization-time of flight-mass spectrometry (SELDI-TOF-MS). Target proteins were purified by SDS-PAGE, and matrix-assisted laser desorption/ionization (MALDI)-TOF-MS was used to determine their amino acid sequences. Protein matches were searched in the SwissProt database. Quantitative polymerase chain reaction (qPCR) and ELISA were employed to confirm the expression of target proteins. Following screening to exclude inflammatory factors, SELDI-TOF-MS revealed a protein with a mass-to-charge ratio of 9,348 Da that was expressed at significantly lower levels in the serum of children with hepatoblastoma compared with healthy controls (P<0.01). Sequence analysis identified this protein as apolipoprotein A-1 (Apo A-I). qPCR and ELISA confirmed that the expression of Apo A-I mRNA and protein were significantly lower in children with hepatoblastoma compared with healthy controls (P<0.05). These results indicate that Apo A-I is a non-inflammatory protein marker for hepatoblastoma with the potential for use in early diagnosis of hepatoblastoma. In addition, the present study demonstrates the feasibility of proteomic screening for the identification of proteins that can serve as markers for a specific tumor.

Identification of apolipoprotein C-I as a potential Wilms' tumor marker after excluding inflammatory factors.

Wilms’ tumor is one of the most common malignant tumors observed in children, and its early diagnosis is important for late-stage treatment and prognosis. We previously screened and identified protein markers for Wilms’ tumor; however, these markers lacked specificity, and some were associated with inflammation. In the current study, serum samples from children with Wilms’ tumors were compared with those of healthy controls and patients with systemic inflammatory response syndrome (SIRS). After exclusion of factors associated with inflammation, specific protein markers for Wilms’ tumors were identified. After comparing the protein peak values obtained from all three groups, a protein with a m/z of 6438 Da was specified. Purification and identification of the target protein using high-pressure liquid chromatography (HPLC) and two-dimensional liquid chromatography-linearion trap mass spectrometry(2D-LC-LTQ-MS) mass spectrometry, respectively, revealed that it was apolipoprotein C-I (APO C-I). Thus, APO C-I is a specific protein marker for Wilms’ tumor.

ApoE and Aβ in Alzheimer’s Disease: Accidental Encounters or Partners?

Among the three human apolipoprotein E (apoE) isoforms, apoE4 increases the risk of Alzheimer's disease (AD). While transporting cholesterol is a primary function, apoE also regulates amyloid-β (Aβ) metabolism, aggregation, and deposition. Although earlier work suggests that different affinities of apoE isoforms to Aβ might account for their effects on Aβ clearance, recent studies indicate that apoE also competes with Aβ for cellular uptake through apoE receptors. Thus, several factors probably determine the variable effects apoE has on Aβ. In this Review, we examine biochemical, structural, and functional studies and propose testable models that address the complex mechanisms underlying apoE-Aβ interaction and how apoE4 may increase AD risk and also serve as a target pathway for therapy.

Protection Against Ischemia/Reperfusion Injury by High-Density Lipoprotein and Its Components

Identification of Apolipoprotein D as a Cardioprotective Gene Using a Mouse Model of Lethal Atherosclerotic Coronary Artery Disease Tsukamoto et al Proc Natl Acad Sci U S A . 2013;110:17023–17028. Apolipoprotein D is expressed in many tissues after injury, such as reperfusion injury after myocardial infarction. Antioxidant activity of apolipoprotein D appears to confer cardioprotective properties after myocardial infarction in a mouse model of severe rapidly progressing coronary atherosclerosis and in a mouse model of ischemia/reperfusion injury. Mice with homozygous-null mutations in the high-density lipoprotein (HDL) scavenger receptor class B type I (SR-BI) and also with homozygous-null mutations in apolipoprotein E (apoE) experience development of severe occlusive coronary atherosclerosis and have myocardial infarction (MI) starting at approximately 31 days after birth. By 42 days after birth, ≈50% have died from cardiac causes. Tsukamoto et al1 studied myocardial gene expression before MI (21 days after birth) and at 31 and 43 days after birth in these mice (SR-BI−/−/apoE−/−). The expression of the gene for osteopontin increased 416-fold, and the gene for apoD increased 80-fold. Because it had previously been reported that the gene for osteopontin increased post-MI,2–5 the authors concentrated on the study of apoD. In an ischemia/reperfusion injury model, adenoviral expression of apoD in the liver was associated with high plasma apoD levels and reduced MI size. In contrast, deficiency of apoD (in apoD-null mice) was associated with increased MI size. The ability of apoD to protect cultured rat cardiomyocytes from hypoxia/reoxygenation injury correlated with the ability of apoD to inhibit oxidation in an in vitro antioxidant assay, suggesting that the antioxidant properties of apoD are important in mediating its cardioprotective properties. The authors determined the time course …

Identification of apolipoprotein D as a cardioprotective gene using a mouse model of lethal atherosclerotic coronary artery disease

Mice with homozygous null mutations in the HDL receptor (scavenger receptor class B, type I, or SR-BI) and apolipoprotein E (apoE) genes [SR-BI/apoE double KO (SR-BI(-/-)/apoE(-/-) or dKO) mice] spontaneously develop occlusive, atherosclerotic coronary artery disease (CAD) and die prematurely (50% mortality at 42 d of age). Using microarray mRNA expression profiling, we identified genes whose expression in the hearts of dKO mice changed substantially during disease progression [at 21 d of age (no CAD), 31 d of age (small myocardial infarctions), and 43 d of age (extensive myocardial infarctions) vs. CAD-free SR-BI(+/-)/apoE(-/-) controls]. Expression of most genes that increased >sixfold in dKO hearts at 43 d also increased after coronary artery ligation. We examined the influence and potential mechanism of action of apolipoprotein D (apoD) whose expression in dKO hearts increased 80-fold by 43 d. Analysis of ischemia/reperfusion-induced myocardial infarction in both apoD KO mice and wild-type mice with abnormally high plasma levels of apoD (adenovirus-mediated hepatic overexpression) established that apoD reduces myocardial infarction. There was a correlation of apoD's ability to protect primary cultured rat cardiomyocytes from hypoxia/reoxygenation injury with its potent ability to inhibit oxidation in a standard antioxidation assay in vitro. We conclude that dKO mice represent a useful mouse model of CAD and apoD may be part of an intrinsic cardioprotective system, possibly as a consequence of its antioxidation activity.

The identification of apolipoprotein C-I in rare minnow (Gobiocypris rarus) and its expression following cadmium exposure

Cadmium (Cd) is a ubiquitous environment contaminant that has been detected in a variety of terrestrial and aquatic organisms. In our study, rare minnow were exposed to 0.4mg/L Cd2+ solution, fish tissues including gill, intestine, kidney, liver, muscle, and spleen were collected at 1, 6, 12, 24 and 48h after exposure. Differential expression sequence tags (ESTs) were screened and an EST similar to Hemibarbus mylodon apolipoprotein C-I (ApoC-I) was identified. The ApoC-I cDNA had been obtained with the sequence of 583bp, which can code 84 amino acids. The transcription expression patterns of ApoC-I were compared after Cd exposure with the real-time PCR in the above tissues. ApoC-I regulation was prominent in spleen, muscle, gill and liver and moderate in kidney and intestine. This suggests a complex transcriptional regulation of ApoC-I expression following Cd exposure.

The screening and identification of Apolipoprotein A-II from serum differential proteins in hepatocellular carcinoma patients

To screen differential proteins in serum from hepatocellular carcinoma (HCC) patients by Proteomic Technology and to purify and identify them. Surface enhanced laser desorption Ionization time of flight-mass spectrum (SELDI-TOF-MS) was employed to screen differential proteins in serum from 33 HCC patients and 33 control cases, and then to purify and identify them using isoelectric precipitation, Tricine sodium dodecyl sulphate polyacrylamide gel electrophoresis (Tricine-SDS-PAGE) and high performance liquid chromatography tandem Mass Spectrum (HPLC-MS). 65 protein peaks in the range of relative molecular weight from 2,000 to 10,000 were found significant difference (P less than 0.05) between the patient group and control group. Based on these differential protein peaks, diagnostic model for HCC detection was established and its sensitivity and specificity were 100% and 96.97% respectively. Proteins with 8,706.5 and 8,579.2 relative molecular weights (the t value was 2.562 and 2.783 respectively, and P value was 0.013 and 0.015 respectively) out of the 65 differential proteins were purified and identified, and then recognized as Apolipoprotein AII (Apo AII). Apo AII is probably a differential protein of HCC and maybe related to the pathogenesis of HCC.

Identification of apolipoprotein C-I in rainbow trout seminal plasma

Three distinct bands with high electrophoretic migration rates were isolated and purified from rainbow trout seminal plasma. The molecular masses of these bands were determined to be 5158.8, 4065.9 and 4929.0 Da. The N-terminal amino acids sequences were elucidated and were found to have high homology with Atlantic salmon apolipoprotein C-I. It can be concluded that apolipoprotein C-I is a major component of rainbow trout seminal plasma. Further studies are necessary to confirm the protective effects of apolipoprotein C-I on spermatozoa in terms of the stabilisation of the sperm membrane.