Berrettini W H, Prozialeck W, Vogel W H
Arch Gen Psychiatry. 1978 May;35(5):600-5. doi: 10.1001/archpsyc.1978.01770290082007.
Platelet monoamine oxidase (MAO) was kinetically evaluated in chronic schizophrenics and matched controls, using substrates of major physiologic importance and substrates of particular interest in the study of schizophrenia, such as serotonin (5-ht), N,N-dimethyltryptamine (DMT), 5-methoxytryptamine (5-MT), and dopamine (DA). Substrates were measured at six concentrations; values for maximal velocity (Vmax) and Michaelis constant (Km) were obtained by using Lineweaver-Burk plots. The Vmax was decreased for all substrates in chronic schizophrenia and the Km was decreased for DA, 5-HT, and DMT, but remained unchanged for 5-MT. The value of Km/Vmax was similar for schizophrencis and normal persons when DA, 5-HT, and DMT were used as substrates, which may indicate that "uncompetitive" inhibition is responsible for the observed decrease in activity among chronic schizophrenics. The finding of a decreased Vmax but unchanged Km with 5-MT would be consistent with noncompetitive inhibition.
使用对生理具有重要意义的底物以及在精神分裂症研究中特别感兴趣的底物，如血清素（5-羟色胺，5-ht）、N，N-二甲基色胺（DMT）、5-甲氧基色胺（5-MT）和多巴胺（DA），对慢性精神分裂症患者和匹配的对照组进行了血小板单胺氧化酶（MAO）的动力学评估。在六个浓度下测量底物；通过使用Lineweaver-Burk图获得最大速度（Vmax）和米氏常数（Km）的值。在慢性精神分裂症中，所有底物的Vmax均降低，DA、5-HT和DMT的Km降低，但5-MT的Km保持不变。当使用DA、5-HT和DMT作为底物时，精神分裂症患者和正常人的Km/Vmax值相似，这可能表明“非竞争性”抑制是慢性精神分裂症患者中观察到的活性降低的原因。5-MT的Vmax降低但Km不变的发现与非竞争性抑制一致。
