英语翻译Detergent solubilized extracts of the cochleae of adult gerbils （Meriones unguiculatus） contain a tyrosine hydroxylase activity measurable by the radiometric method of Pomerantz.This activity is not related to Fenton-type reactions,si

英语翻译Detergent solubilized extracts of the cochleae of adult gerbils （Meriones unguiculatus） contain a tyrosine hydroxylase activity measurable by the radiometric method of Pomerantz.This activity is not related to Fenton-type reactions,si
英语翻译
Detergent solubilized extracts of the cochleae of adult gerbils （Meriones unguiculatus） contain a tyrosine hydroxylase activity measurable by the radiometric method of Pomerantz.This activity is not related to Fenton-type reactions,since it is not inhibited by free radical scavengers and is heat and protease sensitive.It does not appear to be related to a peroxidase(EC 1.11.1.7) since it is neither dependent on H2O2 ,nor inhibited by catalase (EC 1.11.1.6).The involvement of a tyrosine hydroxylase (EC 1.14.16.2) related to catecholamine synthesis is also unlikely,since the activity is highly sensitive to 2-mercaptoethanol and is not increased by addition of tetrahydrobiopterin.The activity in crude inner ear extracts displayed an unusual maturation behaviour,with a slow activation upon aging at 4℃.Fully active enzyme displayed Michaelis-Menten kinetics,with a Km for L-tyrosine of 47 μM.Cochlear tyrosine hydroxylase,but not melanoma tyrosinase （EC 1.14.18.1）,was inhibited by o-phenanthroline,and was not dependent on L-DOPA as cofactor for full enzymatic activity.Crude
extracts were also able to catalyze L-DOPA oxidation and melanin formation from either L-tyrosine or L-DOPA.The tyrosine hydroxylase,DOPA oxidase and melanin formation activities most probably resided in the same molecule,as suggested by inhibition studies.A tyrosine hydroxylase and melanin formation activity with identical properties was found in primary cultures of stria Íascularis melanocytes.Immunochemical evidence confirmed the absence of either the tyrosinase encoded for by the albino locus,or the tyrosinase isoenzyme TRP1,encoded for by the brown locus.Conversely,an immunorreactive band of molecular weight 70 kDa was specifically recognized by a tyrosinase polyclonal antiserum in
Western blot experiments.These results prove that melanogenesis in the cochlea,and likely in other extracutaneous locations such as the brain,is catalyzed by enzymatic systems different from,but related to tyrosinase.1997 Elsevier Science B.V.

英语翻译Detergent solubilized extracts of the cochleae of adult gerbils （Meriones unguiculatus） contain a tyrosine hydroxylase activity measurable by the radiometric method of Pomerantz.This activity is not related to Fenton-type reactions,si
成年的沙土鼠(Meriones unguiculatus)的cochleae的洗涤剂solubilized选段包含一项以波梅兰茨的放射性测量的方法可测量的tyrosine hydroxylase 活动.因为自由基捡破烂的人不抑制热和蛋白酶是敏感的,这项活动与芬顿类型反应没有关系.因为这两个依赖H2O2都不,它似乎不与peroxidase(EC 1.11.1.7)有关,也不通过catalase(EC 1.11.1.6)抑制.与catecholamine 综合有关的tyrosine hydroxylase(EC 1.14.16.2)的介入也不太可能,因为活动非常对2－mercaptoethanol敏感并且没被通过添加tetrahydrobiopterin增加.活动在天然内耳内选出有慢的活动在老化上在4摄氏度显示一异常成熟行为.完全活性的酶展示米凯利斯-Menten动力学,带有47μM的L -tyrosine的一公里.耳蜗的tyrosine hydroxylase,但不是黑瘤tyrosinase(1.14.18.1 EC),o phenanthroline抑制,作为cofactor适合深浓的酶催的活动不依赖L 多巴是.粗制的选段也能从L -tyrosine或者L 多巴中催化L 多巴氧化和黑色素形成.tyrosine hydroxylase,多巴oxidase 和黑色素形成活动最有可能居住在相同分子,以抑制建议研究.tyrosine hydroxylase 和有相同的特性的黑色素形成活动被在蚢scularis melanocytes 辉纹的主要文化里发现.Immunochemical 证据确认缺乏或者为通过白化体地点或者tyrosinase isoenzyme TRP1把进行编码,为通过棕色的地点把进行编码的tyrosinase.
相反,一immunorreactive 分子重量70 kDa的乐队明确一tyrosinase polyclonal 抗血清在西的污点实验内认出.这些结果在耳蜗里证明那melanogenesis,并且在象大脑那样的其他extracutaneous 位置可能,被不同于酶催的系统催化,但是与tyrosinase有关.1997 Elsevier 科学B.V.
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