NOVEL PROSTAGLANDIN DEHYDROGENASE IN RAT SKIN
NOVEL PROSTAGLANDIN DEHYDROGENASE IN RAT SKIN
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DOI：
10.1042/bj2120129
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发表时间：
1983-01-01
影响因子：
4.1
通讯作者：
CAMP, R
中科院分区：
文献类型：
--
作者：
FINCHAM, N;CAMP, R
目前的证据表明，皮肤是前列腺素[PG]代谢的重要器官。为了阐明其作用，以NAD+或NADP+作为共底物，研究了大鼠皮肤15-羟基前列腺素脱氢酶（PGDH）的基本动力学。PGF2.alpha.和PGE_2为底物，初步研究了还原型共底物NADH和NADPH的抑制作用。使用放射化学测定法，其中[3 H] PGF 2 α.或[14 C] PGE 2与大鼠皮肤匀浆的高速上清液一起孵育。然后通过溶剂分配提取底物和产物，通过TLC分离并通过液体闪烁计数定量。在线性反应速率和NAD+浓度为10 mM时，PGF 2 α的平均表观Km为和24 μ M，平均表观Vmax为9.8nmol/s/l反应混合物。对于PGE 2，平均表观Km为8 μ M，平均表观Vmax为2.7nmol/s/l反应混合物。用NADP+作为共底物，浓度为5 mM，获得PGF 2 α的平均表观Km为23 μ M。平均表观Vmax为5.2 nmol/s/l。对于PGE 2，分别获得7.5 μ M和3.0 nmol/s/l的值。皮肤含有NAD+和NADP+依赖性PGDH。一个重要的发现是，NADP+连接的酶给出的PGE 2的Km值大大低于来自其他组织的NADP+连接的PGDH的Km值。用NAD+连接的PGDH系统进行的初步抑制研究表明，这种酶不仅被NADH抑制，而且被NADPH抑制，这是以前没有报道过的来自其他组织的NAD+连接的PGDH的特性。
Present evidence suggests that skin is an important organ of prostaglandin [PG] metabolism. To clarify its role, the basic kinetics of 15-hydroxyprostaglandin dehydrogenase (PGDH) from rat skin were investigated with either NAD+ or NADP+ as co-substrate. PGF2.alpha. and PGE2 were used as substrates and preliminary studies were made of the inhibitory effects of the reduced co-substrates NADH and NADPH. A radiochemical assay was used in which [3H]PGF2.alpha. or [14C]PGE2 were incubated with high-speed supernatant of rat skin homogenates. The substrate and products were then extracted by solvent partition, separated by TLC and quantified by liquid-scintillation counting. At linear reaction rates and at an NAD+ concentration of 10 mM the mean apparent Km for PGF2.alpha. and 24 .mu.M with a mean apparent Vmax of 9.8 nmol/s per l of reaction mixture. For PGE2 the mean apparent Km was 8 .mu.M, with a mean apparent Vmax of 2.7 nmol/s per l of reaction mixture. With NADP+ as a co-substrate at a concentration of 5 mM a mean apparent Km of 23 .mu.M was obtained for PGF2.alpha. with a mean apparent Vmax of 5.2 nmol/s per l. For PGE2 values of 7.5 .mu.M and 3.0 nmol/s per l were obtained, respectively. Skin contains NAD+- and NADP+-dependent PGDH. An important finding was that the NADP+-linked enzyme gave Km values for PGE2 that were considerably lower than those reported for NADP+-linked PGDH from other tissues. Preliminary inhibition studies with the NAD+-linked PGDH system indicate that this enzyme is not only inhibited by NADH, but also by NADPH, a property not previously reported for NAD+-linked PGDH derived from other tissues.