Asparagine selective measurement

Aqueous media, glutamine and asparagine selective measurement by near-IR spectroscopy, 116-130 Ascorbic acid, role in electroenzymatic sensing of fructose using fructose dehydrogenase immobilized in self-assembled monolayer on gold, 85,8 Asparagine selective measurement in aqueous media by near-IR spectroscopy absorption bands, 118-119 apparatus, 117... 

Selective Measurement of Glutamine and Asparagine in Aqueous Media by Near-Infrared Spectroscopy... 

Decarboxylases of phenylalanine, tyrosine, and lysine and ammonia lyases of histidine, glutamine, and asparagine are also highly selective. Guilbault et al. (1988) described a potentiometric enzyme sensor for the determination of the artificial sweetener aspartame (L-aspartyl-L-phen-ylalanine methylester) based on L-aspartase (EC 4.3.1.1). The ammonia liberated in the enzyme reaction created a slope of 30 mV/decade for the enzyme-covered ammonia sensitive electrode. The specificity of the sensor was excellent however, the measuring time of 40 min per sample appears not to be acceptable. The measuring time has been decreased to about 20 min by coimmobilizing carboxypeptidase A with L-aspartase (Fatibello-Filho et al., 1988). 

Asparagine and glutamine can be measured simultaneously by NIR spectroscopy with standard errors of prediction of only 0.18 mM and 0.10 mM as well as mean percent errors of 2.50% and 2.00%, respectively. This level of analysis is possible inspite of the chemical and spectroscopic similarities between these two amino acids. The successfiil measurement of these confounds suggests that NIR spectroscopy is capable of excellent selectivity which will be critical for further expanding this methodology for measuring multiple conq)onents in the complex matrices associated with bioreactors. 

---