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Abstrak :
Sel kanker adalah sel yang berproliferasi secara progresif, dan salah satu dasar pengendaliannya hingga saat ini yaitu dengan menghambat kemampuan proliferasinya melalui intervensi sintesis nukleotida purin/pirimidin menggunakan analog purin/pirimidin. Avidin, suatu protein yang ditemukan pada putih telur, diketahui dapat mengikat biotin dengan sangat kuat, yang merupakan koenzim pada reaksi karboksilasi, suatu tahapan penting di biosintesis de novo nukleotida purin. Studi sebelumnya membuktikan bahwa viabilitas dan proliferasi sel mononuklear darah tepi (SMDT) dapat dihambat dengan penambahan avidin yang diakibatkan gangguan ketersediaan biotin. Studi ini bertujuan melihat efek pemberian avidin terhadap sel kanker kolorektal HT-29 dilihat dari viabilitas, proliferasi, ekspresi gen dan protein cyclin D1, serta siklus sel. Penelitian dilakukan dengan mengultur sel kanker kolorektal HT-29 dengan avidin, lalu dianalisis viabilitas, proliferasi, ekspresi gen dan protein cyclin D1, serta siklus selnya pada 24, 48, dan 72 jam. Didapatkan hasil bahwa avidin menghambat viabilitas dan proliferasi sel HT-29, serta menurunkan ekspresi gen dan protein cyclin D1 pada sel HT-29, namun tidak memengaruhi transisi fase G0/G1 ke fase S siklus sel HT-29. ......Cancer cells are progressively proliferating cell, and up to now, one way to control its proliferation is by intervening the formation of purine/pyrimidine nucleotide using its purine/pyrimidine analog. Avidin, a protein from white egg, known to bind biotin strongly, whereas biotin is an important coenzyme in carboxylation reaction, a key step in purine nucleotide de novo pathway. Previous study showed that viability of peripheral blood mononuclear cells (PBMC) was reduced and its proliferation was inhibited caused by lack of biotin due to avidin administration. This study aims to observe the effect of avidin administration to HT-29 cells viability, proliferation, cyclin D1gene and protein expression, also the cell cycle. The experiment done by culturing HT-29 cells, then its viability, proliferation, cyclin D1 gene and protein expression, also the cell cycle analyzed at 24, 48, and 72 hours. The result showed that avidin halted HT-29 cells viability and proliferation, also lower its cyclin D1 gene and protein expression, but did not affect the transition between G0/G1 phase to S phase on HT-29 cell cycle

Abstrak :
Avidin merupakan glikoprotein tetrametrik yang belakangan ini banyak dikembangkan aplikasinya karena sifatnya yang menguntungkan, terutama dalam bidang biomedis. Senyawa yang dapat digunakan sebagai agen pengenal dalam sensor avidin adalah biotin. Biotin diketahui dapat berikatan seara spesifik dengan avidin (Kd ~10−15 M). Nanopartikel core-shell dapat digunakan sebagai bahan label magnetik yang dapat menunjang pembentukan sensor. Pada penelitian ini, dilakukan sintesis Fe3O4@Au-sisteamin dan studi literatur Fe3O4@Au-sisteamin sebagai template pengikatan biotin untuk sensor avidin. Nanopartikel Fe3O4 di sintesis menggunakan metode ko-presipitasi sedangkan Fe3O4@Au di sintesis melalui deposisi-presipitasi dimana dari kedua metode ini mempermudah pemisahan antara nanopartikel dengan larutan menggunakan magnet eksternal. Nanokomposit hasil sintesis dikarakterisasi dengan spektroskopi Fourier Transform Infrared (FTIR), X-Ray Diffraction (XRD), dan Transmission Electron Microscope (TEM). Hasil yang diperoleh menunjukkan rata-rata nanopartikel Fe3O4 dan Fe3O4@Au sebesar 3,724 ± 0,561 nm dan 13,801 ± 4,147 nm. Hasil FT-IR memunculkan spektra pada bilangan gelombang 550-700 cm-1 yang mengindikasikan bahwa sisteamin berikatan secara kovalen dengan shell Au. ......Avidin is a tetrametric glycoprotein that has been developed recently for many applications because of its beneficial properties, especially in the biomedical field. The compound that can be used as a recognition agent in avidin sensing is biotin. Biotin is well-known to bind specifically with avidin (Kd ~ 10−15 M). In this research, the synthesis of Fe3O4@Au-cysteamine and the literature study of Fe3O4@Au-cysteamine as a biotin binding template for avidin sensor have been done. Fe3O4 nanoparticles (Fe3O4 NPs) were synthesized using the co-precipitation method while Fe3O4@Au were synthesized through precipitation-deposition. Both methods facilitate separation between the nanoparticles and the solution using an external magnet. The synthesized nanocomposites were characterized by Fourier Transform Infrared (FTIR) spectroscopy, X-Ray Diffraction (XRD), and Transmission Electron Microscope (TEM). The results obtained showed that the average Fe3O4 and Fe3O4@Au nanoparticles were 3.724 ± 0.561 nm and 13.801 ± 4.147 nm. The FT-IR spectra also showed that there was peak at 550-700 cm-1 which indicate that cysteamine binds covalently to the Au shell.

Abstrak :
Tiamin berfungsi sebagai koenzim untuk beberapa enzim yang terlibat dalam metabolisme karbohidrat. Mengingat pentingnya peran tiamin, maka dilakukan pengembangan teknik pengukuran tiamin yang analog dengan enzyme linked immunosorbent assay ( ELISA), dimana antibodi diganti dengan protein pengikat spesifik yaitu protein ikat tiamin kacang hijau (PITKH). Teknik pengukuran ini dilakukan secara kompetitif, kompetitor akan dikompetisikan dengan tiamin bebas yang akan diukur. Kompetitor tersebut berupa konjugat antara tiamin-biotin. Tiamin murni diikatkan dengan biotin menggunakan senyawa perangkai yaitu glutaraldehid. Pada analisis LC-MS ditemukan 3 puncak, . Puncak ke 3 merupakan konjugat tiamin-biotin. Dibuat kurva standar dan diperoleh persamaan garis lurus dengan nilai R2= 0,9986. Uji validasi menggunakan konjugat tiamin-biotin menunjukan nilai coefficient of variation (CV) = 3,81%, nilai ini lebih kecil dari CV Horwitz = 8,12%, akurasi dengan nilai Recovery (R) =94 %-98%. Hasil ini menunjukan syarat pengukuran dengan teknik ELPLA sudah terpenuhi, dengan presisi dan akurasi yang baik. Aplikasi pengukuran kadar tiamin pada serum normal sebanyak 23 sampel didapatkan kadar tiamin berkisar 2,62-9,76 μg/ml. Dengan demikian, teknik ELPLA dengan konjugat tiamin-biotin sebagai kompetitor dapat digunakan pada pengukuran kadar tiamin dalam serum ......Thiamine has a coenzyme function in several enzymes involved in carbohydrate metabolism. Considering the important role of thiamine, a thiamine measurement technique analogous to the enzyme linked immunosorbent assay (ELISA) was developed, that the antibody was replaced by a specific binding protein named mung bean thiamine binding protein (MBTBP). The measurement technique was carried out competitively in which competitors would be competed with free thiamine to be measured. The competitor is a thiamine-biotin bond. Pure thiamine was bound to biotin using a coupling compound called glutaraldehyde. In the LC-MS analysis we found 3 peaks. The third peak was the thiamine-biotin conjugate. A standard curve was made and the value of its straight line equation was obtained R2= 0,9986. The validation test using thiamine-biotin conjugate showed coefficient of variation (CV) value = 3,81% which was smaller than Horwitz CV = 8,12%, with the accuracy of the Recovery (R) value = 94% – 98%. These results indicated that the measurement requirements for the ELPLA technique had been met with good precision and accuracy. The application of the serum measurements to 23 samples showed thiamine levels ranging from 2,62- 9,76 μg/ml. Thus, the ELPLA technique with thiamine-biotin conjugate as a competitor could be used in the measurement of serum thiamine levels