Sensuła Barbara M, Derrick Peter J, Bickerton John C, Pazdur Anna
Silesian University of Technology, Institute of Physics, Department of Radioisotopes, Krzywoustego 2, 44-100 Gliwice, Poland.
Rapid Commun Mass Spectrom. 2009 Jul;23(13):2070-4. doi: 10.1002/rcm.4089.
We present the first results concerning interannual variations in concentrations of glucose and cellobiose, obtained through enzymatic hydrolysis of alpha-cellulose. The alpha-cellulose was extracted from late-wood of oak. The tree-ring chronologies, wood components and their physical and chemical properties provide information about the ecosystem in which the tree grew, and thus information regarding climate variability and the impact of human activity in the past. The large molecular size and insolubility make it difficult to determine precisely the chemical and physical properties of the intact cellulose polymer. Enzymatic hydrolysis is the principal method of degradation of cellulose. In this study the feasibility has been examined of characterizing alpha-cellulose through analysis by mass spectrometry (MS) of the degradation products from hydrolysis. Degradation of alpha-cellulose was possible without using alkaline or acid buffers. Analysis by MS provided the opportunity to obtain information on the biodegradation of saccharides. The presence of cellobiose and glucose in the degradation product was evidenced by the mass spectra. We have compared the abundances of these glucose and cellobiose ions with carbon isotope ratios, the efficiency of extraction of alpha-cellulose from the wood and tree-ring width indices. The challenge is to establish, with respect to climate changes and environmental conditions, the significance of the variations from one year to another in the observed abundances of glucose and cellobiose ions.
我们展示了通过α-纤维素酶水解获得的葡萄糖和纤维二糖浓度年际变化的首批结果。α-纤维素是从橡木晚材中提取的。树木年轮年代学、木材成分及其物理和化学性质提供了有关树木生长生态系统的信息，从而也提供了过去气候变异性和人类活动影响的信息。纤维素聚合物完整时，其大分子尺寸和不溶性使得精确测定其化学和物理性质变得困难。酶水解是纤维素降解的主要方法。在本研究中，已通过对水解降解产物进行质谱分析（MS）来检验表征α-纤维素的可行性。无需使用碱性或酸性缓冲液即可实现α-纤维素的降解。质谱分析提供了获取糖类生物降解信息的机会。质谱图证实了降解产物中存在纤维二糖和葡萄糖。我们将这些葡萄糖和纤维二糖离子的丰度与碳同位素比率、从木材中提取α-纤维素的效率以及树木年轮宽度指数进行了比较。面临的挑战是，针对气候变化和环境条件，确定观察到的葡萄糖和纤维二糖离子丰度逐年变化的意义。
