Boc-L-Tirozin Toz Kristalinin Gama Işınlaması Sonrası Elektron Paramanyetik Rezonans (EPR) Spektroskopik İncelemesi

Öz

Bu çalışmada, peptit sentezinde yaygın olarak kullanılan korumalı amino asit türevi N-(tert-bütoksikarbonil)-L-tirozinin (Boc-L-Tirozin) gama ışınlaması sonucu oluşan serbest radikaller Elektron Paramanyetik Rezonans (EPR) spektroskopisi kullanılarak incelenmiştir. Toz kristal örnek oda sıcaklığında 60Co gama kaynağı ile 10 kGy dozunda ışınlanmış ve oluşan paramanyetik merkezler X-band EPR spektrometresi ile analiz edilmiştir. Deneysel spektrumun simülasyonu sonucunda aşırı ince yapı etkileşme sabitleri aCH = 0.45 mT ve aN = 0.13 mT, çizgi genişliği ΔH = 0.40 mT ve spektroskopik yarılma faktörü g = 2.0054 olarak belirlenmiştir. Elde edilen EPR parametreleri, ışınlama sonucunda oluşan paramanyetik merkez ĊH(NH)COOH radikaline atfedilmiştir. Eşleşmemiş elektronun α-karbon üzerinde lokalize olduğu ve oluşan radikalin karbon merkezli bir α-aminoalkil radikali ile uyumlu olduğunu göstermektedir. Geniş tek çizgili spektrumun gözlenmesi, çizgi genişliğinin α-proton aşırı ince yapı sabitine yakın, azot aşırı ince yapı sabitinden ise belirgin şekilde büyük olmasına bağlanmıştır. Çalışma, gama ışınlanmış Boc-L-Tirozin'de oluşan radyasyon kaynaklı radikallerin EPR yöntemiyle karakterizasyonuna ilişkin yeni deneysel veriler sunmaktadır. Ayrıca örneğin biyolojik ve kimyasal özellikleri detaylı bir şekilde ele alınmıştır.

Anahtar Kelimeler

• Elektron Paramanyetik Rezonans
• Serbest Radikal
• Amino Asit Türevleri

Electron Paramagnetic Resonance (EPR) Spectroscopic Investigation of Gamma-Irradiated Boc-L-Tyrosine Powder Crystal

Öz

In this study, radiation-induced free radicals generated in N-(tert-butoxycarbonyl)-L-tyrosine (Boc-L-Tyrosine), a protected amino acid derivative widely used in peptide synthesis, were investigated by Electron Paramagnetic Resonance (EPR) spectroscopy. Powder crystal samples were irradiated at room temperature with a dose of 10 kGy using a 60Co gamma-ray source, and the resulting paramagnetic centers were analyzed using an X-band EPR spectrometer. Simulation of the experimental spectrum yielded hyperfine coupling constants of aCH = 0.45 mT and aN = 0.13 mT, a linewidth (ΔH) of 0.40 mT, and a spectroscopic splitting factor (g) of 2.0054. Based on these EPR parameters, the radiation-induced paramagnetic center was assigned to the ĊH(NH)COOH radical. The results indicate that the unpaired electron is localized on the α-carbon atom, consistent with the formation of a carbon-centered α-aminoalkyl radical. The observation of a single broad resonance line was attributed to the linewidth being comparable to the α-proton hyperfine coupling constant and considerably larger than the nitrogen hyperfine coupling constant, thereby preventing the resolution of the hyperfine structure. The present study provides new experimental EPR data for the characterization of radiation-induced radical species in gamma-irradiated Boc-L-Tyrosine. In addition, the chemical and biological properties of the investigated compound are comprehensively reviewed to provide a broader perspective on its structural characteristics and potential applications.

Anahtar Kelimeler

• Elektron Paramagnetic Resonance
• Free Radical
• Amino Acid Derivatives

Kaynakça

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