Wu Ping, Stenman Ulf-Håkan, Pakkala Miikka, Närvänen Ale, Leinonen Jari
Department of Clinical Chemistry, Helsinki University Central Hospital, Helsinki, Finland.
Prostate. 2004 Mar 1;58(4):345-53. doi: 10.1002/pros.10337.
Prostate-specific antigen (PSA) is a serine protease with highly prostate-specific expression and an important marker for prostate cancer. We have previously identified novel PSA-binding peptides that enhance the enzymatic activity of PSA when produced as fusion proteins.
PSA-binding peptides and derivatives with a spacer were chemically synthesized and used to prepare an affinity column, which was used to fractionate PSA in seminal plasma, serum, and LNCap cell culture medium.
Approximately 67% of seminal plasma PSA bound to the peptide affinity column and was eluted under mild conditions. Eluted PSA was intact and enzymatically active while the unbound fraction mainly contained various nicked forms. ProPSA from LNCap cells bound to the peptide column only after activation by trypsin.
PSA-binding peptides can be used to separate enzymatically active and inactive forms of PSA. Thus the peptides are potentially useful as ligands for development of methods for specific detection of active free PSA.
前列腺特异性抗原（PSA）是一种丝氨酸蛋白酶，具有高度的前列腺特异性表达，是前列腺癌的重要标志物。我们之前已经鉴定出新型PSA结合肽，当作为融合蛋白产生时，这些肽可增强PSA的酶活性。
化学合成带有间隔区的PSA结合肽及其衍生物，并用于制备亲和柱，该亲和柱用于分离精浆、血清和LNCap细胞培养基中的PSA。
约67%的精浆PSA与肽亲和柱结合，并在温和条件下洗脱。洗脱的PSA完整且具有酶活性，而未结合部分主要包含各种缺口形式。LNCap细胞中的前PSA仅在被胰蛋白酶激活后才与肽柱结合。
PSA结合肽可用于分离PSA的酶活性和无活性形式。因此，这些肽有可能作为配体，用于开发特异性检测活性游离PSA的方法。
