滴定量热法研究氨基酸羧基质子化反应

氨基酸是典型的两性物质,其羧基质子化常数已有报道,文献结果大都由pH电位法得到,而对氨基酸光学异构体(D、L、DL)的对比研究甚少,为检验光学活性起源理论中提出的D与L分子间的能量差异,我们曾用微量量热技术观察了苯丙氨酸、亮氨酸。

利用特征氨基酸组分分析与显微观察鉴别掺假鱼粉

通过显微镜检观察,发现两类掺假鱼粉中分别含有海泥颗粒或羽毛碎片等杂质。氨基酸分析结果表明,掺假鱼粉的氨基酸总量和蛋氨酸、赖氨酸、苏氨酸、色氨酸等必需氨基酸含量大幅度降低,造成氨基酸组分不平衡;掺入海泥的鱼粉中芳香族氨基酸——酪氨酸含量不到合格鱼粉正常值的1/4,而掺入羽毛粉的鱼粉,丝氨酸、胱氨酸、脯氨酸等含量反而比优质鱼粉的正常含量还要高。分析结果还表明,优质或合格鱼粉中检出丰富的牛磺酸(637.4～746.8 mg·hg-1),而掺假鱼粉中牛磺酸含量只有33.27～43.76 mg·hg-1,不到正常值的1/10,可以作为特征性指标成分进行鱼粉是否掺假的检测分析。采用氨基酸组分分析技术结合显微镜观察可以准确鉴别掺假鱼粉。

微扰理论计算氨基酸和糖水溶液的密度

基于微扰理论并借助于统计缔合流体理论的基本思路,建立了氨基酸和糖水溶液密度的状态方程.计算了甘氨酸、丙氨酸、缬氨酸、氨基丁酸和丝氨酸水溶液体系在4个温度下的密度,以及葡萄糖、果糖、半乳糖、树胶醛糖和木糖水溶液体系在5个温度下的密度.此外采用所建立的方程,不引入任何可调参数,直接对氨基酸在尿素水溶液中的密度进行了预测.关联和预测的结果均令人满意.

Excitatory amino acid on secondary spinal cord injury: effect anmechanism

Sprague-Dawley rats were subjected to traumatic spinal cord injury using Allen's method. Regional concentrations of excitatory amino acid (EAA) were assessed by high-performance liquid chromatography, and regional water and ion content were measured by the atomic absorption spectrophotometry at various times after intrathecal administration of different dosage of 3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP),a specific antagonist of N-methyl-D-aspartame (NMDA) receptor,to rat at 48 h posttrauma.The results showed that concentrations of glutamate and aspartate were elevated rapidly at 15, 30 min and were correlated positively with the severity of injury. In the injured segment there was a significant increase in water, Na+ ,Ca++ content and a decrease in K+ , Mg++. Whereas in CPP treated groups they had a statistically significant return, which was related to the dosage and time of administration. This effect of CPP suggests that ion and water content were related to overactivation of NMDA receptor. Excessive high levels of EAA may be involved in secondary tissue damage following spinal cord injury.

7-氨基-1-羟基萘-3-磺酸(γ酸)衍生的酸性染料的合成及其性能研究

本文涉及由γ酸衍生的,在分子中含有磺酰胺基的红色酸性染料的合成。该类染料构想用来在弱酸性染浴中染聚酰胺和羊毛纤维。通过检测染料的应用性能。坚牢度和光谱特性,发现磺酰胺基和在它的氮原子上的取代基会影响该类染料的性能。