A Study on Glucose-6-Phosphate Dehydrogenase Enzyme Activity

Yıl 2018, Cilt: 9 Sayı: 34, 54 - 60, 01.09.2018

Elmas Öğüş , Mehmet Sezai Kuş

https://doi.org/10.17944/mkutfd.387715

Öz

Aim:Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common erythrocyte enzyme deficiency in the world. It is the most common cause of hemolytic anemia in our country especially in the Mediterranean region. Most patients with enzyme deficiency have no clinical symptoms. However, hemolytic state develops in the red blood cells due to drugs, infections, favism, newborn period which cause oxidative damage. In our study, we aimed to investigate G6PD enzyme activity and kinetic properties.

Material and Method:G6PD enzyme activity was measured qualitatively with a fluorescence spot test and quantitatively in a G6PD deficient blood sample and in a control blood sample, and partial enzyme purification was performed to compare kinetic characteristics. 

Results: No fluorescence was observed qualitatively in the blood sample with enzyme deficiency. Enzyme activity measured quantitatively in the sample with G6PD deficiency was statistically significantly lower than the control (p <0.05). The kinetics of the partially purified deficient enzyme were found to have lower Km values (G6P and NADP) than in the normal enzyme. The other kinetic characteristics of enzyme of deficient G6PD activity in comparison with normal enzyme were; a higher optimum pH, more activity with the substrate analogs and a lower thermostability.

Conclusion:G6PD enzyme deficiency is important in the diagnosis and monitoring of the patient in terms of public health and preventive medicine.

Anahtar Kelimeler

Glucose-6-phosphate dehydrogenase, enzyme deficiency, kinetic properties

Glukoz-6-Fosfat Dehidrogenaz Enzim Aktivitesi Üzerine Bir Çalışma

Öz

Amaç: Glukoz-6-fosfat dehidrogenaz (G6PD) eksikliği, dünyada en çok rastlanan eritrosit enzim eksikliğidir. Ülkemizde özellikle Akdeniz bölgesinde görülen hemolitik anemilerin en sık nedenidir. Enzim eksikliği olan hastaların çoğunda klinik belirti yoktur. Ancak alyuvarlarda oksidatif hasara yol açan ilaçlar, enfeksiyonlar, bakla yenmesi, yenidoğan dönemi gibi nedenlerle hemolitik tablo gelişir. Çalışmamızda G6PD enzim aktivitesi ve kinetik özelliklerini araştırmak amaçlandı.

Gereç ve Yöntem: G6PD enzim aktivitesi floresan spot testi ile kalitatif olarak ve kantitatif olarak ölçülen G6PD eksikliği olan bir kan örneği ve bir kontrol kan örneğinde kısmi enzim saflaştırması yapılarak kinetik özellikleri karşılaştırıldı. 

Bulgular: Enzim eksikliği bulunan kan örneğinde kalitatif olarak floresans gözlenmedi. G6PD eksikliği olan örnekte kantitatif olarak ölçülen enzim aktivitesi kontrole göre istatistiksel olarak anlamlı düzeyde düşük bulundu (p<0.05). Kısmen saflaştırılan hasta G6PD enziminin G6P ve NADP için Km ve Vm değerleri normal enzime göre daha düşük bulundu. Hasta enziminin diğer kinetik özellikleri; normal enzime oranla alkalen pH’da daha yüksek aktivite, substrat benzerlerini daha yüksek oranda kullanabilme ve daha düşük termostabilite idi.

Sonuç: Halk sağlığı ve koruyucu hekimlik açısından G6PD enzimi eksikliği hastanın tanısı ve izlenmesinde önem taşır.

Anahtar Kelimeler

Glukoz-6-fosfat dehidrogenaz, enzim eksikliği, kinetik özellikler

Kaynakça

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