Terashima M, Hara N, Badruzzaman M, Shimoyama M, Tsuchiya M
Department of Biochemistry, Shimane Medical University, Izumo, Japan.
FEBS Lett. 1997 Jul 21;412(1):227-32. doi: 10.1016/s0014-5793(97)00784-9.
Arginine-specific ADP-ribosyltransferase present in granules of chicken polymorphonuclear leukocytes (so-called heterophils) is released into the extracellular space by stimulus of calcium ionophore A23187 or opsonized zymosan [Terashima et al. (1996) J. Biochem. 120, 1209-1215]. In the present work, we examined extracellular targets of the released transferase and identified tuftsin, a phagocytosis-stimulating tetrapeptide derived from leukokinin, as a preferential substrate of the enzyme in chicken plasma. Specific binding of FITC-tuftsin to murine peritoneal macrophages, observed under a fluorescent microscope, was impaired by ADP-ribosylation of the labelled peptide. Phagocytic assay analyzed by flow cytometry revealed that ADP-ribosylation of tuftsin decreased its phagocytosis-stimulating activity towards the macrophages. Thus, the ADP-ribosylation of tuftsin apparently decreases its biological activity and ADP-ribosylation may possibly be involved in inflammatory processes through alterations in tuftsin activity.
存在于鸡多形核白细胞（所谓的异嗜性粒细胞）颗粒中的精氨酸特异性ADP-核糖基转移酶，在钙离子载体A23187或调理酵母聚糖的刺激下释放到细胞外空间[寺岛等人（1996年）《生物化学杂志》120卷，第1209 - 1215页]。在本研究中，我们检测了释放的转移酶的细胞外靶点，并确定了促吞噬四肽tuftsin（一种源自白细胞激肽的促吞噬四肽）是该酶在鸡血浆中的优先底物。在荧光显微镜下观察到，FITC - tuftsin与小鼠腹腔巨噬细胞的特异性结合因标记肽的ADP - 核糖基化而受损。通过流式细胞术分析的吞噬试验表明，tuftsin的ADP - 核糖基化降低了其对巨噬细胞的促吞噬活性。因此，tuftsin的ADP - 核糖基化明显降低了其生物活性，并且ADP - 核糖基化可能通过改变tuftsin的活性而参与炎症过程。
