Modifikasi Protein Akibat Pembebanan Glukosa dengan Model Reaksi Glikosilasi Nonenzimatik in vitro

Abstract

Glycocylation reaction causes protein modification. Glycocylation is a reaction between aldehyde group from reducing sugar with amine group of protein. The aim of this study was to measure Advanced Glycation End Products (AGEs) formation, dicarbonyl compound and tyrosine degradation in glycocylation reaction in vitro. A quasi experimental study was done to four treated groups, i.e. P1= 5 ml Bovine Serum Albumin (BSA), 10 ml phosphate buffer dan 10 ml aquadest; P2= 5 ml BSA, 10 ml phosphate buffer and 10 ml glucose 125 mM; P3= 5 ml BSA, 10 ml phosphate buffer and 10 ml glucose 250 mM; P4= 5 ml BSA, 10 ml phosphate buffer and 10 ml glucose 500 mM. AGEs compound was measured for 21 days using spectrophotometer at X = 390 nm. Dicarbonyl compound was measured by DNPH odification methods at X = 470 nm. Tyrosine degradation was measured usingMillon-Nasse reaction. Anova and Tuckey HSD test concluded there are significant difference between each groups (P<0,05). Based on correlation regresion test conclude that the increase of dicarbonyl compounds, AGEs and tyrosine degradation had positive correlation with increase of glucose concentration. Glucose overloading could induce protein modification in vitro.

Salah satu penyebab modifikasi protein adalah reaksi glikosilasi. Reaksi glikosilasi adalah reaksi antara gugus aldehid gula pereduksi dengan gugus amina protein. Penelitian ini bertujuan mengukur Advanced Glycation End Products (AGEs), senyawa dikarbonil maupun degradasi tirosin pada reaksi glikosilasi in vitro. Penelitian ini merupakan penelitian eksperimental semu denganpre andpost control group design terhadap empat kelompok perlakuan, yaitu P1= 5 ml Bovine Serum Albumin (BSA), 10 ml buffer fosfat dan 10 ml aquadest; P2= 5 ml BSA, 10 ml buffer fosfat dan 10 ml glukosa 125 mM; P3= 5 ml BSA, 10 ml buffer fosfat dan 10 ml glukosa 250 mM; P4= 5 ml BSA, 10 ml buffer fosfat dan 10 ml glukosa 500 mM. Absorbansi senyawa AGEs diukur selama 21 hari pada X = 340 nm sedangkan absorbansi senyawa dikarbonil diukur dengan X = 390 nm dan absorbansi degradasi tirosin dengan k=470 nm. Pengukuran absorbansi senyawa dikarbonil menggunakan metoda DNPH yang dimodifikasi, sedangkan pengukuran degradasi tirosin menggunakan reaksi Millon-Nasse. Berdasarkan hasil uji Anova dan Beda Nyata Jujur, disimpulkan bahwa terdapat perbedaan yang signifikan (P<0,05) tiap kelompok perlakuan. Berdasarkan uji korelasi regresi dapat disimpulkan bahwa pembentukan senyawa dikarbonil, AGEs dan degradasi tirosin berkorelasi positif dengan peningkatan konsentrasi glukosa. Pembebanan glukosa yang berlebih dapat memicu modifikasi protein in vitro.