Gu K F, Chang T M
Artificial Cells and Organs Research Centre, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
Appl Biochem Biotechnol. 1990 Nov;26(2):115-24. doi: 10.1007/BF02921527.
A multienzyme system consisting of leucine dehydrogenase (EC 1.4.1.9), L-lactic dehydrogenase (EC 1.1.1.27), urease (EC 3.5.1.5), and dextran-NAD+ was microencapsulated within artificial cells. This system could convert ammonia and urea into essential amino acids, L-leucine, L-valine, and L-isoleucine. L-lactate acted as a cosubstrate for the regeneration of dextran-NADH. Greater concentrations of L-lactate favored the higher conversion ratios. The effects of ammonium salts and urea on reaction rate were also studied. The relative reaction rates in ammonium salts solutions were 44.6-78.8% of those in urea solutions. More than 90% of the original activity was retained when artificial cells were kept at 4 degrees C for 6 wk.
由亮氨酸脱氢酶（EC 1.4.1.9）、L-乳酸脱氢酶（EC 1.1.1.27）、脲酶（EC 3.5.1.5）和葡聚糖-NAD⁺组成的多酶系统被微囊化在人工细胞内。该系统可将氨和尿素转化为必需氨基酸，即L-亮氨酸、L-缬氨酸和L-异亮氨酸。L-乳酸作为葡聚糖-NADH再生的共底物。较高浓度的L-乳酸有利于提高转化率。还研究了铵盐和尿素对反应速率的影响。铵盐溶液中的相对反应速率为尿素溶液中的44.6 - 78.8%。当人工细胞在4℃保存6周时，超过90%的原始活性得以保留。
