title: Two urinary peptides associated closely with type 2 diabetes mellitus.
abstract: OBJECTIVE
  To monitor of type 2 diabetes more simply, conveniently and noninvasively, we are trying to identify the potential urinary peptides that associated with different stages of glucose control in type 2 diabetes mellitus.
  
  
  METHODS
  Firstly, we collected urine samples from type 2 diabetic patients and normal controls. These type 2 diabetic patients were divided into two groups according to fasting plasma glucose (FPG) and hemoglobin A1c% (HbA1c), respectively. Magnetic beads based weak cation exchange chromatography (MB-WCX) was used to condense urinary peptides. The eluates were then analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Subsequently, ClinProt was used to profile and screen the polypeptide patterns based on different methods of grouping in diabetic patients and normal controls. Finally, the amino acid sequences of differentially expressed peptides were identified by nano-liquid chromatography-tandem mass spectrometry and the protein sources of the corresponding peptide were matched in IPI Human database.
  
  
  RESULTS
  Proteomics analysis found two up-regulated peptide (m/z 2756.1 and m/z 3223.2) representations in diabetic subjects, and the two peptides increased with increases in the amount of glycosylated hemoglobin. Further, the parallelism between m/z 3223.2 and glycosylated hemoglobin was better than the parallelism between m/z 2756.1 and glycosylated hemoglobin. Area under the receiver operating characteristic of the two peptides was 0.722 and 0.661, respectively. The above-mentioned peptide m/z 2756.1 was further identified as fragment of fibrinogen alpha chain precursor and m/z 3223.2 was fragment of prothrombin precursor.
  
  
  CONCLUSIONS
  These results suggested the two urinary biomarkers enable monitor of type 2 diabetes patients with different stages of glucose control.
authors.affiliation: Department of Clinical Laboratory, Peking University Ninth School of Clinical Medicine, Beijing Shijitan Hospital, Beijing, China; Department of Clinical Laboratory, Beijing Shijitan Hospital, Capital Medical University, Beijing, China.
authors.forename: Man
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Department of Clinical Laboratory, Peking University Ninth School of Clinical Medicine, Beijing Shijitan Hospital, Beijing, China.
authors.forename: Guangzhen
authors.initials: G
authors.lastname: Fu
authors.affiliation: Department of Clinical Laboratory, Peking University Ninth School of Clinical Medicine, Beijing Shijitan Hospital, Beijing, China; Department of Clinical Laboratory, Beijing Shijitan Hospital, Capital Medical University, Beijing, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Lei
mesh_terms: D000595:Amino Acid Sequence; D001786:Blood Glucose / Q000378:metabolism; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000652:urine*; D005215:Fasting / Q000097:blood / Q000652:urine; D005260:Female; D005786:Gene Expression Regulation; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000652:urine*; D040901:Proteomics; D012372:ROC Curve
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; D010455:Peptides; C517652:hemoglobin A1c protein, human