犬心脏组织中的NAD糖水解酶活性。

NAD glycohydrolase activity in dog cardiac tissue.

Calva E, Núñez R, Briones E, Marsch M

Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados, Instituto Politécnico Nacional, Mexico, D.F.

Comp Biochem Physiol B. 1978;61(1):173-9. doi: 10.1016/0305-0491(78)90237-7.

Abstract

Dog heart tissue suspension hydrolyzes NAD, NADP and NMN, and releases nicotinamide stoichiometrically. 2. Maximum activity was observed at 50 degrees C and the activation energy was 10 kcal/mol. 3. Optimum pH range was 6.2-7.6. 4. Compounds with adenine-ribose moiety increased the enzymatic activity. 5. Nicotinamide released during incubation produced reaction nonlinearity. 6. Km for NAD and NADP were about the same; Vmax was higher for NAD. Similar findings have been reported for rabbit heart. 7. Dog enzyme appears to be more sensitive than the rabbit enzyme to noncompetitive inhibitors. 8. Pyrophosphatase activity was not detected in dog heart in contrast to rabbit and rat heart preparations.

摘要

犬心脏组织悬液可水解NAD、NADP和NMN，并按化学计量比释放烟酰胺。2. 在50℃时观察到最大活性，活化能为10千卡/摩尔。3. 最适pH范围为6.2 - 7.6。4. 含有腺嘌呤 - 核糖部分的化合物可提高酶活性。5. 孵育过程中释放的烟酰胺导致反应非线性。6. NAD和NADP的Km大致相同；NAD的Vmax更高。兔心脏也有类似的发现。7. 犬酶似乎比兔酶对非竞争性抑制剂更敏感。8. 与兔和大鼠心脏制剂不同，在犬心脏中未检测到焦磷酸酶活性。