Ortín F, Giralt M, Cervelló I, Nogués M R, Puerto A M, Argany N, Mallol J
Unidad de Farmacología, Facultad de Medicina, Universidad Rovira i Virgili, Reus, Tarragona.
Med Clin (Barc). 1996 Apr 27;106(16):607-10.
Erythrocytic glutathion S-transferase (GST) plays an important role as a protective mechanism against oxidative stress. The present study was conducted to evaluate the influence of both smoking habit and sex upon the kinetic characteristics of the enzyme.
176 healthy subjects (100 men and 76 women), smokers and nonsmokers, were included. Enzyme parameters were calculated in erythrocytic haemolysates using 1-chloro-2,4-dinitrobenzene (CDNB) and glutathion (GSH) as substrates. Haemoglobin (Hb) was removed by affinity chromatography. In samples coming from 51 men and 42 women the native haemolysate was subjected to thermal shock (52 degrees C) and the enzyme parameters were compared with those obtained in the non-denatured samples.
In non-denatured samples, Km (mM) and Vmax (mumol/min/g Hb) values for CDNB were significantly higher (p < 0.001) in smokers than in non smokers, especially in women. Thus, respectively for Km and Vmax (mean +/- standard deviation): for men non smokers, 1.43 +/- 0.54, 1.63 +/- 0.42 and smokers, 1.74 +/- 0.5, 1.8 +/- 0.69; for women, non smokers 1.42 +/- 0.56, 1.57 +/- 0.46 and smokers, 2.05 +/- 0.59, 2.51 +/- 0.6. Thermal denaturation diminished the enzyme activity in all cases and modified the Km values, these results were opposite to those obtained in the non-denatured samples. Thus, for Km and Vmax respectively: for men, smokers, 1.6 +/- 0.71 and 0.9 +/- 0.32 and non smokers, 1.4 +/- 0.66 and 0.53 +/- 0.29; for women, non smokers, 2.00 +/- 0.58, 1.13 +/- 0.29 and smokers 1.22 +/- 0.77, 0.52 +/- 0.23. The GSt content was similar in the four groups studied (3.75 +/- 1.15 mumol SH/g Hb).
The greater thermolability of GST activity and the increase in the Km values observed in smokers, especially in women, should be considered as indicative of an increased risk for the erythrocytes against oxidative stress.
红细胞谷胱甘肽S-转移酶（GST）作为一种抗氧化应激的保护机制发挥着重要作用。本研究旨在评估吸烟习惯和性别对该酶动力学特性的影响。
纳入176名健康受试者（100名男性和76名女性），包括吸烟者和非吸烟者。以1-氯-2,4-二硝基苯（CDNB）和谷胱甘肽（GSH）为底物，在红细胞溶血产物中计算酶参数。通过亲和色谱法去除血红蛋白（Hb）。对来自51名男性和42名女性的样本，将天然溶血产物进行热休克处理（52℃），并将酶参数与未变性样本中的参数进行比较。
在未变性样本中，吸烟者CDNB的Km（mM）和Vmax（μmol/min/g Hb）值显著高于非吸烟者（p<0.001），尤其是女性。因此，Km和Vmax（平均值±标准差）分别为：男性非吸烟者，1.43±0.54，1.63±0.42；吸烟者，1.74±0.5，1.8±0.69；女性非吸烟者，1.42±0.56，1.57±0.46；吸烟者，2.05±0.59，2.51±0.6。热变性在所有情况下均降低了酶活性并改变了Km值，这些结果与未变性样本中的结果相反。因此，Km和Vmax分别为：男性吸烟者，1.6±0.71和0.9±0.32；非吸烟者，1.4±0.66和0.53±0.29；女性非吸烟者，2.00±0.58，1.13±0.29；吸烟者，1.22±0.77，0.52±0.23。在所研究的四组中GSt含量相似（3.75±1.15μmol SH/g Hb）。
吸烟者尤其是女性中观察到的GST活性更高的热稳定性及Km值增加，应被视为红细胞抗氧化应激风险增加的指标。
