用二氧化碳电极测定霉菌537蛋白酶的活性

在霉菌５３７蛋白酶的作用下，酷蛋白发生水解，生成酪氨酸和谷氨酸等组成该蛋白的氨基酸，加入Ｌ－谷氨酸脱羧酶使谷氨酸发生脱羧反应，会释放出ＣＯ２，后者可用ＣＯ２电极进行测定，从而可间接地算出５３７蛋白酶的活性，在蛋白酶活性为２０００－１０００单位范围内，电位的变化值与活性呈现良好的线性关系。     

盐胁迫对甜高粱幼苗抗氧化酶活性的影响

研究了不同浓度NaCl溶液(含量0、50、100、150 mmol/L)处理对4种甜高粱幼苗超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性以及脂质过氧化产物丙二醛含量的影响。结果表明,与对照相比(即NaCl浓度为0),50 mmol/L NaCl处理显著增加了SOD、POD和CAT活性,而100和150 mmol/L NaCl处理则抑制了3种抗氧化酶活性。NaCl胁迫导致了脂质过氧化发生,具体表现为随着NaCl处理的浓度增加,丙二醛也增加。4种供试甜高粱对NaCl胁迫的应答有差异,其中辽甜1号在所有供试浓度的NaCl胁迫下,3种抗氧化酶活性均高于其他3个品种,而丙二醛含量最低,表明辽甜1号对NaCl的耐受性是最强的。     

Enzymology of NAD+ homeostasis in man

This review describes the enzymes involved in human pyridine nucleotide metabolism starting with a detailed consideration of their major kinetic, molecular and structural properties. The presentation encompasses all the reactions starting from the de novo pyridine ring formation and leading to nicotinamide adenine dinucleotide (NAD⁺) synthesis and utilization. The regulation of NAD⁺ homeostasis with respect to the physiological role played by the enzymes both utilizing NAD⁺ through the nonredox NAD⁺-dependent reactions and catalyzing the recycling of the common product, nicotinamide, is discussed. The salient features of other enzymes such as NAD⁺ pyrophosphatase, nicotinamide mononucleotide 5-nucleotidase, nicotinamide riboside kinase and nicotinamide riboside phosphorylase, described under miscellaneous, are likewise presented.Received 30 April 2003; received after revision 9 June 2003; accepted 20 June 2003     

Heparan sulfate-protein interactions: therapeutic potential through structure-function insights

Heparin and the related glycosaminoglycan, heparan sulfate, bind a myriad of proteins. The structural diversity of heparin and heparan sulfates is enormous, but differences in the conformational flexibility of the monosaccharide constituents add extra complexity and may influence protein binding. Silencing genes for heparin/ heparan sulfate biosynthetic enzymes profoundly affects mammalian development. Thus, altering the structure of heparan sulfate chains can alter protein binding and embryo development. Different heparan sulfate structures are located in particular tissue sites, and these structures are recognised by different sets of proteins. Regulation of certain heparan sulfate-protein interactions by pH or cations is described. Heparin/heparan sulfate structures are viewed as potential therapeutics for a variety of diseases. An understanding at the molecular and functional levels of the specificity and affinity of heparan sulfate-protein interactions is crucial for designing heparin-inspired drugs. How the development of synthesis techniques is facilitating structure-function analyses and drug development is discussed.Received 6 July 2004; received after revision 16 September 2004; accepted 28 September 2004     

Sex pheromone conversion and degradation in antennae of the silkworm mothBombyx mori L.

Summary In living antennae of the silkworm mothBombyx mori L. the pheromone compound (E, Z)-10,12-hexadecadienol and hexadecanol are enzymatically converted to their corresponding fatty aldehydes, acids and long-chain fatty acid esters. The pheromone is completely degraded at high rates in the antennae of freshly hatched moths. The polar volatile [³H]metabolites exclusively consist of tritiated water. The half-life of the pheromone is about 2.5 min in males and 0.5 min in females. Drying inactivates the enzymes responsible for pheromone oxidation.Dedicated to Professor Adolf Butenandt on the occasion of his 85th birthday     

黑曲霉果胶酶的研究 Ⅱ.诱变菌株607的产酶条件实验

对诱变菌株607果胶酶的产生条件进行了试验,酶活性水平为3000u/g 以上。     

Mitochondrial abnormalities in fibroblast line GM3093 defective in oxidative metabolism

Summary Fibroblast line GM3093 deficient in the activity of the pyruvate dehydrogenase complex, was derived from a patient reported to have an inherited defect affecting the tricarboxylic acid cycle. Our results suggest a generalized defect consisting of few and abnormal mitochondria and low activities of all mitochondrial enzymes examined.Preliminary reports of aspects of this work appeared as abstracts in Trans. Am. Soc. Neurochem.15 (1984) 178, and Soc. Neurosci.10 (1984) 996.Developmental and Metabolic Neurology Branch.Surgical Neurology Branch.     

侧耳菌产生木质纤维素酶及其降解植物生物质的研究

对在液体培养基中产生木质纤维素降解酶能力强且产酶速度较快的侧耳 sp 2 (Pleurotussp 2 )进行了最佳产酶液体培养基组分的研究 ,并对其在液体培养基、固体培养基中产生木质纤维素降解酶能力和行为进行了分析 .结果表明 ,该菌株在低氮高碳高无机盐培养基中的锰过氧化物酶、木质素过氧化物酶、漆酶和半纤维素酶等 4种酶的活性最高 .其中 ,锰过氧化物酶的活性峰值出现时间仅为 6 d,比其他 3种酶活性峰值期早 6 d. Pleurotus sp 2是目前已知的在液体培养条件下产锰过氧化物酶较高的菌株之一 .当该菌株培养在含有低氮无碳高无机盐液体培养基的麦草粉中时 ,锰过氧化物酶和漆酶的活性峰值均出现在第 10天 ,而半纤维素酶的活性在 4 0 d时达到峰值 .此外 ,该菌株使麦草生物质失重可达 17.6 % ,可望能成为生物制浆中原料预处理的候选菌株     

外电场影响酶活性机制初探

用电子－构象相互作用理论研究了外电场影响酶活性的分子机理，并讨论了相关的问题，结构表明强外场有利于激发酶的活性。     

Short cerebral ischemia and subsequent reperfusion and treatment with stobadine

Lipid peroxidation and activities of antioxidative enzymes were studied in the brain cortex after short (15 min) cerebral ischemia and reperfusion (10 min) in rats. Conjugated dienes (CD) and thiobarbituric acid-reactive substances (TBARS) were significantly elevated in the group of rats with ischemia followed by reperfusion in comparison to the ischemic animals. Superoxide dismutase (SOD) activity significantly increased in the group of animals with ischemia and reperfusion. No significant changes in the activities of glutathione peroxidase (GP) were observed. Stobadine administered before ischemia or before reperfusion decreased the level of TBARS. Stobadine probably prevents malondialdehyde (MDA) formation from hydroperoxide or might elevate the activity of aldehyde dehydrogenase. In contradiction to the findings after long-lasting (4 h) ischemia and subsequent reperfusion¹, no decrease in the concentration of CD or in the activity of SOD or GP was found.