鱼肌肉醛缩酶的酶学性质

Enzymatic properties of fish muscle aldolase.

Nakagawa T, Nagayama F

Department of Food Science and Technology, Faculty of Fisheries, Tokyo, University of Fisheries, Japan.

Comp Biochem Physiol B. 1989;92(2):405-10. doi: 10.1016/0305-0491(89)90301-5.

Abstract

Aldolases were isolated from the ordinary muscle of red sea bream Pagrus major, Pacific mackerel Scomber japonicus, and carp Cyprinus carpio by ammonium sulfate fractionation, followed by ion-exchange chromatography on DEAE-cellulose and CM-Sepharose CL-6B columns, and examined for enzymatic properties. 2. The aldolases showed the highest activity in a pH range from 6.8-7.8 Km values for fructose-1,6-bisphosphate ranged from 0.025-0.10 mM. 3. Irrespective of fish species, aldolase activity was inhibited by ATP, ADP, and AMP. ATP showed the strongest inhibition and was competitive with fructose-1,6-bisphosphate. 4. The aldolases did not require divalent metal ions for activation and were completely inhibited at 0.1 mM Cu2+. 5. Thermal inactivation of the enzymes was of the first-order reaction. Red sea bream, Pacific mackerel and carp enzymes lost the activity by 50% when incubated at 50 degrees C for 8, 14 and 23 min, respectively.

摘要

通过硫酸铵分级分离，随后在DEAE - 纤维素和CM - Sepharose CL - 6B柱上进行离子交换色谱法，从真鲷、太平洋鲭和鲤鱼的普通肌肉中分离出醛缩酶，并对其酶学性质进行了研究。2. 醛缩酶在pH 6.8 - 7.8范围内表现出最高活性，果糖 - 1,6 - 二磷酸的Km值在0.025 - 0.10 mM之间。3. 无论鱼类种类如何，醛缩酶活性均受到ATP、ADP和AMP的抑制。ATP表现出最强的抑制作用，并且与果糖 - 1,6 - 二磷酸具有竞争性。4. 醛缩酶不需要二价金属离子激活，在0.1 mM Cu2+时完全被抑制。5. 酶的热失活为一级反应。真鲷、太平洋鲭和鲤鱼的酶在50℃分别孵育8、14和23分钟时活性丧失50%。