权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

A Study of Methionine Sulfoxide-Reducing Ability in Ruminant Animals

反刍动物蛋氨酸亚砜还原能力的研究

基本信息

批准号：
61560328
负责人：
ONODERA Ryoji
金额：
$ 1.15万
依托单位：
University of Miyazaki
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1988
项目状态：
已结题

项目摘要

Methionine sulfoxide (MSO) is recognized to be available as a methionine source for mammals. The present study was designed to demonstrate a hypothesis that ruminant animals might have higher MSO reductase activity than did monogastric animals.At first, optimal conditions for assaying the enzyme activities were examined using the livers and kidneys of both catle and swine slaughtered in a meat plant in Miyazaki city. Since the enzyme activity was found chiefly in homogenate and supernatant fluid after centrifugation in bth tissues of both animals, the supernatant fluid was used hereafter for assaying the activity. Optimum PH and temperature examined were as follows: cattle liver: PH 6.0, 33 C; cattle kidney: PH 6.7, 39 C; swine liver and kidney: PH 7.0, 37 c. The effects of reducing agents on the activity examined were shown to be that both in cattle and swine, NADH and NADPH equally stimulated the activity in liver, while only NADPH did in kidney. The substrate concentrations (mM) for obtaining the maximum velocity (activity) and Km (mM) examined under the optimum conditions using NADH for liver and NADPH for kidney as reducing agents were as follows: cattle liver: 0.80, 0.158; cattle kidney: 0.60, 0.064; swine liver: 0.25, 0.049; swine kidney: 1.00, 0.116.Finally, under the conditions to gain the maximum activity (but temperature was fixed at 39 c), 17 heads of cattle and 12 heads of swine were supplied for determining the average enzyme activities of both animals. As a result, though the activty of swine appeared to show relatively centralized values, the activity in cattle varied from animal to animal. This point led us to presume that MSO reductase might be an inducible enzyme. Taking an average, the activity of cattle liver (expressed as nmol of methionine per unit weight of the tissue) was 3.6 times higher than that of swine liver, and cattle kidney was 1.15 times as high as swine kidney.

二甲亚砜（MSO）被认为是哺乳动物的蛋氨酸来源。本研究旨在证明反刍动物可能比单胃动物具有更高的MSO还原酶活性的假设。首先，使用在宫崎市肉类工厂屠宰的猫和猪的肝脏和肾脏，研究了测定酶活性的最佳条件。由于在两只动物的bth组织中主要在匀浆和离心后的上清液中发现酶活性，因此下文使用上清液测定活性。试验的最适pH和温度为：牛肝：pH6.0，33 ℃，牛肾：pH6.7，39 ℃，猪肝和猪肾：pH7.0，37 ℃。还原剂对酶活性的影响表明，在牛和猪中，NADH和NADPH对肝脏酶活性有同等的促进作用，而只有NADPH对肾脏酶活性有促进作用。获得最大速度的底物浓度（mM）在最佳条件下，用肝脏的NADH和肾脏的NADPH作为还原剂，测定的酶活和Km（mM）如下：牛肝：0.80，0.158;牛肾：0.60，0.064;猪肝：0.25，0.049;猪肾：最后，在获得最大酶活性的条件下（但温度固定在39 ℃），提供17头牛和12头猪用于测定两种动物的平均酶活性。因此，虽然猪的活性似乎显示出相对集中的值，但牛的活性因动物而异。这一点使我们推测MSO还原酶可能是一种诱导酶。平均而言，牛肝的活性（以每单位组织重量的甲硫氨酸nmol表示）是猪肝的3.6倍，牛肾是猪肾的1.15倍。