Regulating function of coenzymization and decoenzymization of the lactate dehydrogenase isozymes in the mouse tissues during hypoxia.
OBJECTIVE
To study the characteristics of changes of LDH enzyme patterns of mice under slight hypoxia.


METHODS
Mice treated with artificial hypoxia, various tissues were made for the test of LDH enzymatic activity by the specific staining technique. LDH (1-5) relative percentage enzymatic activity (RPEA) were measured with CS-910 dual-wavelength thin layer chromatography scanner.


RESULTS
The RPEA of LDH isozymes of various tissues after slight hypoxia shifted to the isozymes LDH1 and LDH2, whose principal subunits are H subunits, and the RPEA of LDH1 (H4), LDH2 (H3M) increased, while RPEA of LDH5 (M4) in various tissues decreased prominently except the cardiac muscle, and that of LDH4 (HM3) decreased as well. After polyacrylamide gel electrophoresis (PAGE) of the hypoxia treated cardiac muscle specimen was made, activity subbands originated regularly in the isoyme patterns of LDH, with the regularity of LDH1 (0 subband), LDH2 (0-1 subbands), LDH3 (0-2 subbands), LDH4 (1-3 subbands), LDH5 (2-4 subbands). After adding appropriate amount of NAD+ to the hypoxia treated cardiac muscle specimen, PAGE showed the subbands of four isoymes (LDH2-LDH5) reduced or even totally disappeared in the isozyme patterns.


CONCLUSIONS
The negative feedback regulation of coenzymization and decoenzymization of LDH isozymes is one of the mouse stress responses to slight hypoxia.
Mingxiu
Yuan
Y
College of Life Sciences, College of Chemistry & Molecular Engineering, Peking University, Beijing 100871.
Hui
Jiang
J
Aiping
Deng
D
Qingzhong
Zhou
Z
D000818:Animals; D006614:Hindlimb / Q000201:enzymology; D000860:Hypoxia / Q000201:enzymology*; D007527:Isoenzymes / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000145:classification / Q000378:metabolism*; D008099:Liver / Q000201:enzymology; D051379:Mice; D009132:Muscles / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D011897:Random Allocation
D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase; C409667:lactate dehydrogenase 1