Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Elevated serum prostate-specific antigen (PSA) levels in body fluids may indicate prostate cancer (PCa), but it is noted that the clinical performance is rather poor. Specificity and sensitivity values of 20 and 94% at a cutoff value of 4.1 ng/mL, respectively, result in overdiagnosis and unnecessary interventions. Previous exploratory studies have indicated that the glycosylation of PSA potentially leads to improved PCa diagnosis based on qualitative analyses. However, the applied methods are not suited for a quantitative evaluation or implementation in a medical laboratory. Therefore, in this proof-of-principle study, we have evaluated the use of hydrophilic interaction liquid chromatography (HILIC) in combination with targeted quantitative mass spectrometry for the sialic acid linkage-specific analysis of PSA glyco-proteoforms based on either trypsin or ArgC peptides. The efficiency of PSA proteolysis was optimized as well as the glycopeptide separation conditions (buffer type, strength, and pH). The HILIC-based analysis of PSA glyco-proteoforms presented here has the potential for the clinical validation of patient cohorts. The method shows the feasibility of the use of a HILIC stationary phase for the separation of isomeric glycopeptides to detect specific glyco-proteoforms. This is the first step toward the development and evaluation of PSA glyco-proteoforms for use in a clinical chemistry setting aiming for improved PCa diagnosis or screening.
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PMID:HILIC-MRM-MS for Linkage-Specific Separation of Sialylated Glycopeptides to Quantify Prostate-Specific Antigen Proteoforms. 3214 89

The kallikrein-related peptidase 15 (KLK15) gene is a member of the largest cluster of serine proteases in the human genome. Exhibiting trypsin-like activity, KLK15 is most likely involved in the activation of prostate-specific antigen (PSA; also known as KLK3), an established biomarker for the diagnosis and screening of prostate cancer. High mRNA expression levels of KLK15 have already been reported in ovarian and prostate cancer, in contrast with breast cancer, where KLK15 has been proposed as a biomarker of favorable prognosis. In this study, we exploited the next-generation sequencing (NGS) technology along with 3' rapid amplification of cDNA ends (3' RACE) to discover alternative KLK15 splice variants. Extensive computational analysis of the obtained NGS data revealed the existence of novel splice junctions, thus supporting the existence of novel KLK15 transcripts. Six novel KLK15 splice variants were identified and verified by Sanger sequencing. Two of them (KLK15 v.11 and v.12) contain an open reading frame and are hence predicted to encode two novel KLK15 protein isoforms. Expression analysis of each KLK15 splice variant in sixteen cDNA pools from malignant cell lines and in normal cell lines (HEK293, HaCaT, and BJ cells) revealed very different expression profiles of particular KLK15 transcripts. Moreover, the new KLK15 splice variants were shown to be expressed in breast, ovarian, prostate, urinary bladder, colon, and renal tissue specimens. Due to the prominent clinical value of KLK15 mRNA expression, the novel KLK15 transcripts appear as candidate cancer biomarkers for diagnostic and/or prognostic purposes and, therefore, merit further investigation.
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PMID:Identification of six novel alternative transcripts of the human kallikrein-related peptidase 15 (KLK15), using 3'RACE and high-throughput sequencing. 3233 22


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