Anderson G R, Kovacik W P, Marotti K R
J Biol Chem. 1981 Oct 25;256(20):10583-91.
A novel isozyme of lactate dehydrogenase is detected in various cells transformed by the Kirsten murine sarcoma virus (KiMSV). This isozyme, designated LDHk, is strongly inhibited by physiological concentrations of oxygen, in an apparently cooperative fashion. LDHk is inhibited by guanosine triphosphate and related compounds, in a noncompetitive fashion. LDHk is found with both 35,000- and 22,000-dalton subunits, although these probably cleave from a 57,000-dalton precursor. In studies utilizing a temperature-sensitive transforming gene mutant of the Kirsten sarcoma virus, we find in vivo expression of LDHk is also temperature-sensitive. In studies using either crude cell-free extracts or purified LDHk, we find the enzyme from cells infected with a temperature-sensitive transforming gene mutant of KiMSV is thermolabile relative to that from wild type KiMSV-infected cells.
在由 Kirsten 小鼠肉瘤病毒（KiMSV）转化的各种细胞中检测到一种新型乳酸脱氢酶同工酶。这种同工酶被命名为 LDHk，它受到生理浓度氧气的强烈抑制，且呈现出明显的协同作用方式。LDHk 被三磷酸鸟苷及相关化合物以非竞争性方式抑制。LDHk 由 35000 道尔顿和 22000 道尔顿的亚基组成，尽管这些亚基可能是从 57000 道尔顿的前体裂解而来。在利用 Kirsten 肉瘤病毒温度敏感转化基因突变体进行的研究中，我们发现 LDHk 的体内表达也具有温度敏感性。在使用粗制无细胞提取物或纯化的 LDHk 进行的研究中，我们发现，相对于野生型 KiMSV 感染细胞中的酶，来自感染了 KiMSV 温度敏感转化基因突变体的细胞中的酶对热不稳定。
