臨床酵素学の進歩−血清酵素異常症へのアプローチ(4)

LDH-M サブユニット欠損症

須　藤　加代子*
　　　　　　　　　　　　　　　　　　　　　　
Lactate Dehydrogenase M Subunit Deficiency

Kayoko SUDO, PhD*

Lactate Dehydrogenase(LDH) M subunit deficiency was first discovered by urinary discoloration and discrepancy in laboratory data. The response to ischemic forearm work is characteristic(absence of an increased venous lactate concentration after ischemic work and a marked increase in venous pyruvate are found). The increase of pyruvate concentration is specific to LDH-M subunit deficiency. Glycolysis was markedly retarded in the patient's muscle in the glyceraldehyde 3-phosphate dehydrogenase(GAPDH) step, possibly due to the impaired reoxidation of NADH produced by GAPDH activity. Then the excessive NADH is reoxidized by a -glycerophosphate and glycerol. Therefore, ATP production is significantly impaired and muscle tissue is damaged. Molecular analysis revealed a detection of 20 base-pairs in exon 6 in LDH-M subunit deficiency. This mutation results in a frame-shift translation and premature termination.
[Rinsho Byori 50 : 571〜575, 2002]

*Kokusai Gakuin Saitama Junior College, Saitama 330-8548

【Key Words】lactate dehydrogenase(乳酸脱水素酵素)，subunit(サブユニット)，discrepancy(乖離)，defi-ciency(欠損)，ischemic forearm work(虚血運動負荷試験)

*国際学院埼玉短期大学食物栄養科(〒330-8548 さいたま市吉敷町2-5)

E-mail :kayosudo@kgef.ac.jp