KINETIC PROPERTIES OF PYRUVATE KINASE PURIFIED FROM THE FLESH MUSCLE OF THE ANTARCTIC KRILL EUPHAUSIA SUPERBA DANA (15th Symposium on Polar Biology)

• Main Authors: Rubens ROSA, Jose Miguel ZAMORA, Claudete Deguirmendjian ROSA, Edson RODRIGUES, Metry BACILA
• Format: Report
• Language: English
• Published: Proceeding 1994
• Subjects: Antarctic; The Antarctic; Antarc*; Antarctic Krill; Euphausia superba; Polar Biology; Proceedings of the NIPR Symposium on Polar Biology
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=5221; http://id.nii.ac.jp/1291/00005221/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=5221&item_no=1&attribute_id=18&file_no=1

In previous experiments, BACILA, ROSA, and RODRIGUES showed that enolase, partially purified from the flesh muscle of the krill Euphausia superba DANA, has not been inhibited by F^- in concentrations as high as 2 mM, a property which is paralleled by the enolase from the penguins liver. This finding led to the study of the structure and the kinetic properties of other enzymes from the carbohydrate metabolism of the krill's flesh muscle. In the present communication some data on the kinetic properties of the pyruvate kinase (PK) purified from the krill's flesh muscle are shown. L-Phenylalanine inhibits this preparation of PK both in the presence and in the absence of 1 mM L-alanine. However, the inhibition of PK by Mg-ATP was almost completely reversed in the presence of 1 mM Fru-P_2, but not in the presence of 1 mM L-alanine. The Km values for PK have been established to be 0.03 μM PEP and 0.038 μM PEP respectively in the presence and in the absence of Fru-P_2. This flesh muscle krill's preparation of PK shows clear sigmoidal kinetics. However, in the presence of Fru-P_2, PK shows a Michaelian kinetics. The effect of ADP has also been established and found to have a Km value of 0.15 μM ADP. Cations inhibit the krill's pyruvate kinase in the following order: Mn^<2+>> Ca^<2+>>Ni^<2+>>Co^<2+> while Li^<2+> did not show any inhibitory effect.