TRANSPORT & ENZYMOLOGY OF SULFUR AND NITROGEN COMPOUNDS

我们的研究关注的是新陈代谢的早期步骤 无机硫和氮化合物。主要强调的是ATP 丝状真菌青霉菌的硫酰基酶和APS激酶 产黄霉菌。真菌三磷酸腺苷硫酰基酶已纯化至均一 并在运动学、物理和化学方面进行了部分表征。我们的 目前的努力旨在(A)阐明反应的机理， (B)确定对功能性氨基酸残基负责 酶的完整性，以及(C)探索ATP的潜在相互作用 硫酰基酶和APS激酶。关于ATP的平行研究正在进行中 杜邦青霉(一种嗜热菌)的硫酰基酶。我们与P。 Duponti酶可能会揭示导致这种疾病的因素 该酶具有显著的热稳定性。APS激酶，第二个硫酸盐 从产黄假单胞菌和金黄色葡萄球菌中分离纯化了活性酶。 正在被刻画成。真菌硫酸盐还原途径的研究 将会被启动。其他拟议的项目包括硝酸盐研究。 产黄假单胞菌的还原酶和亚硝酸盐还原酶，特别是 强调这些酶的动力学机制。其中一些方法 将采用的内容包括：(A)稳态和反应分析 进展动力学，(B)与天然和 化学修饰的酶，以及(C)特定的化学修饰 氨基酸残基。

Our research is concerned with the early steps in the metabolism of inorganic sulfur and nitrogen compounds. Major emphasis is on ATP sulfurylase and APS kinase from the filamentous fungus Penicillium chrysogenum. The fungal ATP sulfurylase has been purified to homogeneity and partially characterized kinetically, physically, and chemically. Our current efforts are aimed at (a) elucidating the mechanism of the reaction, (b) identifying the amino acid residues responsible for the functional integrity of the enzyme, and (c) exploring the potential interaction of ATP sulfurylase with APS kinase. Parallel studies are in progress on the ATP sulfurylase from Penicillium duponti (a thermophile). Our work with the P. duponti enzyme may shed some light on the factors responsible for the remarkable heat stability of this enzyme. APS kinase, the second sulfate activating enzyme has been purified to homogeneity from P. chrysogenum and is being characterized. Studies on the sulfate reduction pathway of fungi will be initiated. Other proposed projects include studies on nitrate reductase and nitrite reductase from P. chrysogenum, with particular emphasis on the kinetic mechanisms of these enzymes. Some of the methods that will be employed include (a) analysis of steady-state and reaction progress kinetics, (b) equilibrium ligand binding with native and chemically modified enzymes, and (c) chemical modification of specific amino acid residues.