神经肽催产素的还原与S-亚硝化：对其生物学功能的影响

Reduction and S-nitrosation of the neuropeptide oxytocin: implications for its biological function.

作者信息

Roy Jean-François, Chrétien Michelle N, Woodside Barbara, English Ann M

机构信息

Department of Chemistry and Biochemistry, Centre for Biological Applications of Mass Spectrometry, Concordia University, 7141 Sherbrooke Street W., Montreal, Que., Canada.

出版信息

Nitric Oxide. 2007 Sep;17(2):82-90. doi: 10.1016/j.niox.2007.06.005. Epub 2007 Jul 4.

DOI:10.1016/j.niox.2007.06.005

PMID:17692543

Abstract

Oxytocin (OT; Cys-Tyr-Ile-Gln-Asn-Cys-Pro-leu-Gly), a posterior pituitary peptide hormone, is characterized by a Cys1-Cys6 disulfide bond in its stable, isolated state. This paper describes a simple, one-step method for the production of OT in its reduced, dithiol form (OT dithiol), free of reducing agent. The effects of temperature, pH, and metal-ion chelators on the autoxidation of OT dithiol were examined to establish if this form is likely to persist under biological conditions. It was found that OT dithiol has a half-life of 1.8h with respect to reformation of OT disulfide at 37 degrees C and pH 6.9 in the presence of the copper chelators, DTPA and neocuproine. S-Nitrosation of OT dithiol by acidified nitrite at pH 3.0 was examined by absorption spectroscopy and HPLC-UV-MS, which revealed that both singly and doubly S-nitrosated OT are formed. These results suggest novel chemical aspects to OT signaling, the biological implications of which are discussed here.

摘要

催产素（OT；半胱氨酸-酪氨酸-异亮氨酸-谷氨酰胺-天冬酰胺-半胱氨酸-脯氨酸-亮氨酸-甘氨酸）是一种垂体后叶肽类激素，在其稳定的分离状态下以Cys1-Cys6二硫键为特征。本文描述了一种简单的一步法，用于制备还原态的二硫醇形式的OT（OT二硫醇），且不含还原剂。研究了温度、pH值和金属离子螯合剂对OT二硫醇自氧化的影响，以确定这种形式在生物学条件下是否可能持续存在。发现在铜螯合剂二乙三胺五乙酸（DTPA）和新亚铜试剂存在的情况下，OT二硫醇在37℃和pH 6.9时重新形成OT二硫键的半衰期为1.8小时。通过吸收光谱法和高效液相色谱-紫外-质谱法研究了在pH 3.0时酸化亚硝酸盐对OT二硫醇的S-亚硝化作用，结果表明单S-亚硝化和双S-亚硝化的OT均能形成。这些结果揭示了OT信号传导新的化学特性，本文将讨论其生物学意义。