来自嗜热栖热放线菌的电子供体和硝酸还原酶抑制剂。（注：原文中“Cyanidium caldarium”一般指嗜热栖热放线菌，但该词在生物学中可能有其他准确指代，此处翻译是基于常见释义。若上下文明确其为其他特定生物，翻译需相应调整。）不过按照你要求的格式，准确译文为：来自嗜热栖热放线菌的电子供体和硝酸还原酶抑制剂。（但这里其实是根据常见理解进行的翻译，严格按格式要求，仅从你提供的英文直接翻译为：来自嗜热栖热放线菌的电子供体和硝酸还原酶抑制剂。感觉这样翻译可能不太能让读者完全理解其准确含义，供你参考。）严格按格式要求的最终译文：来自嗜热栖热放线菌的电子供体和硝酸还原酶抑制剂。

Electron donors and inhibitors of nitrate reductase from Cyanidium caldarium.

作者信息

Rigano C, Aliotta G

出版信息

Biochim Biophys Acta. 1975 Mar 28;384(1):37-45. doi: 10.1016/0005-2744(75)90093-5.

Abstract

Studies on nitrate reductase (NAD(P)H:nitrate oxidoreductases EC 1.6.6.2) of Cyanidium caldarium revealed that the enzyme is inhibited by excess of electron donor, NADPH, reduced benzylviologen and FMN. Also dithionite, used to reduce benzylviologen and FMN, inactivates nitrate reductase: however, FMN at an optimal concentration and nitrate, added before the dithionite, protect the enzyme against this inactivation. Cyanide, cyanate and carbamyl phosphate inhibit the enzyme competitively with respect to nitrate, and Ki values are reported. Organic mercurials, 0.1 mM, act preferentially on NADPH activity, whereas Ag+ and Hg-2+ at the same concentration inactivate 80--90% of the benzylviologen and FMN activities. ADP is very poor inhibitor. Urea 4 M in 2 h destroys 90% of the NADPH activity and only 30% of the benzylviologen and FMN activities. The apparent Km values for NADPH, benzylviologen, FMN and nitrate have been determined.

摘要

对嗜热蓝藻硝酸还原酶（NAD(P)H：硝酸氧化还原酶，EC 1.6.6.2）的研究表明，该酶会受到过量电子供体、NADPH、还原型苄基紫精和FMN的抑制。用于还原苄基紫精和FMN的连二亚硫酸盐也会使硝酸还原酶失活：然而，在连二亚硫酸盐之前添加的最佳浓度的FMN和硝酸盐可保护该酶免受这种失活作用。氰化物、氰酸盐和氨基甲酰磷酸相对于硝酸盐竞争性抑制该酶，并报告了Ki值。0.1 mM的有机汞优先作用于NADPH活性，而相同浓度的Ag+和Hg2+会使80%-90%的苄基紫精和FMN活性失活。ADP是非常弱的抑制剂。4 M尿素在2小时内会破坏90%的NADPH活性，而仅破坏30%的苄基紫精和FMN活性。已测定了NADPH、苄基紫精、FMN和硝酸盐的表观Km值。