苯丙氨酸羟化酶基因突变分析及与临床严重度相关性的研究

目的:检测苯丙酮尿症(PKU)患者苯丙氨酸羟化酶(PAH)基因突变谱,探讨其突变率与临床严重度的相关性.方法:53例PKU患者根据其治疗前的血苯丙氨酸浓度进行临床分型,同时提取其基因组DNA,PCR扩增PAH基因外显子3、5、6、7、10、11和12,用单链构像多态分析、变性高效液相层析(DHPLC)和直接测序3种方法筛查PAH基因突变.用Kendall等级相关分析临床严重度和突变基因型的相关性.结果:4种突变(R176X、E280K、L367R和S349A)在中国PKU人群中未见报道,其中2种突变(L367R和S349A)为国际首次报道.基因型和临床严重度之间具有较好的相关性(r=0.696,P＜0.01).结论:新发现的PKU患者的4种基因新突变,丰富了PKU患者PAH基因突变谱.基因型和临床严重度间较好的相关性为临床上PKU的基因诊断提供了重要的理论依据.DHPLC法是一种快速、准确、经济的筛选PAH基因突变的新方法.     

Nutritional factors affecting serum phenylalanine concentration during pregnancy for identical twin mothers with phenylketonuria

The effect of energy, protein, fat, and phenylalanine on serum phenylalanine concentrations during pregnancy for a set of identical twins with phenylketonuria (PKU) was examined. Blood samples were collected one to two times per week. The subjects completed a 3-d food record prior to each blood collection. The effect of the factors on serum phenylalanine levels was evaluated statistically using time-series analysis. Dietary intakes of the nutrients evaluated were similar for the subjects. For one subject, there were highly significant effects of energy, protein, and fat on serum phenylalanine levels. In contrast, these nutrients had no significant effect on serum phenylalanine for the other subject. Dietary phenylalanine had no significant effect on serum phenylalanine for either twin. Conclusions: There was no effect of phenylalanine intake and no consistent effect of energy, protein, or fat on serum phenylalanine. Other dietary or environmental factors or a combination of factors may impact serum phenylalanine levels of pregnant women with PKU.     

中国人苯丙氨酸羟化酶基因的10种新突变

目的 研究中国人苯丙氨酸羟化酶(PAH)基因突变的分子基础。方法 应用PCR／SSCP、序列分析等技术,分析中国北方地区120个经典型苯酮尿症(PKU)核心家系,对PAH基因外显子3、5、7、10、11、12进行突变基因的筛查和确定。结果 在确定的31种突变中(另文报道)有10种突变首次在中国PKU人群中发现：165T、S70del、G239D、R241fsdelG、L255S、P281L、G346R、L367fsinsC、R400S和Ivsllnt2t→c。其中4种突变G239D、R241fsdelG、R400S和Ivsllnt2t→c在国际PAH数据库末见公布(至投稿日期)。新突变显示中国人PAH基因虽以点突变为主,但存在小的碱基插入、缺失以及移码突变。新突变主要发生在外显子7中(4／10),每种突变的发生频率均很低(0．42％。1．3％)。结论 中国人PAH基因存在高度异质性和突变的多样性,外显子7是PAH基因的突变热点区域。     

人苯丙氨酸羟化酶基因克隆及其原核表达质粒的构建

[目的]克隆健康人苯丙氨酸羟化酶基因全长cDNA序列,构建并鉴定其原核表达质粒pTrcHisB/PAH。[方法]采用RT-PCR方法从人肝组织中扩增PAH基因全长cDNA,T/A克隆到pMD18-T载体中,双酶切后将cDA亚克隆入pTrcHisB载体,构建pTrcHisB/PAH质粒,经限制性内切酶鉴定并测序。[结果]人PAH基因cDNA正确克隆入pTrcHisB表达载体,与Genebank中PAH基因序列一致。[结论]成功构建pTrcHisB/PAH表达质粒,为进一步进行研究PAH蛋白表达和重组蛋白活性鉴定奠定基础。     

Monoliths with chiral surface functionalization for enantioselective capillary electrochromatography

The state-of-the-art in CEC enantiomer separations with monolithic capillary columns is comprehensively reviewed. The various types of monolithic columns comprising in situ organic polymer monoliths, molecularly imprinted polymer (MIP) monoliths, silica monoliths and monoliths made from particles are discussed with a focus on materials’ synthesis, chemistry and properties as well as column aspects. Monolithic MIP-type porous layer open-tubular (PLOT) columns are treated herein as well. From this survey of the literature, the authors come to the conclusion that monolithic silica capillaries appear to become the preferred column type for CEC enantiomer separations of low-molecular drugs and other chiral pharmaceuticals or chemicals.     

Synthesis of four diastereomeric enkephalins incorporating cyclopropyl phenylalanine

Four diastereomeric D-Ala²,Leu⁵-enkephalins have been synthesized and their CD spectra and rat brain binding affinities determined. Only the peptides containing Z-cyclopropyl phenylalanine residues showed strong binding affinity. No correlation between CD spectra and bioactivity could be made.     

EFFECTIVE INVERSION OF LEFT HEART REMODELING BY PHENYLALANINE IN ESSENTIAL HYPERTENSION

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Tetrahydrobiopterin and Parkinson''s disease

Two patients with Parkinson's disease were treated with 1 g tetrahydrobiopterin (BH4) for 5 days. Clinical improvement was not observed. In the cerebrospinal fluid (CSF) a 4-8 fold increase in the concentration of homovanillic acid (HVA), and a 3-fold increase in the concentration of 5-hydroxyindole acetic acid (5-HIAA) was measured. However, the concentration of HVA reached, was only approximately half as high, as that of patients treated with madopar (DOPA + benserazid). In urine, the excretion of HVA increased 13-37 fold, when the patients were treated with madopar, whereas no increase in the HVA excretion was measured after the BH4 administration. Additionally, 2 patients with Parkinson's disease were treated with 1 g BH4 in combination with 15 g tyrosine for 3 days, and 1 parkinsonian patient was treated with 15 g tyrosine daily for 7 weeks. No increase in the CSF concentrations of HVA or 5-HIAA was observed. The results suggest, the BH4 in the dosage used, is not effective in the treatment of Parkinson's disease.     

Preparations,solution conformations and molecular structures of N,N′-ethylene-bridged dipeptides and their derivatives

The solution conformations of novel dipeptides, methyl (2S, 3′S)-3-methyl-2-(2′-oxo-3′-isopropyl-1′-piperazinyl)-butanoate (EVV-OCH₃), methyl (2S, 3′S)-3-phenyl-2-(2′-oxo-3′-benzyl-1′-piperazinyl) propionate (EFF-OCH₃), and their derivatives (Boc-Gly-EW-OH, Boc-Gly-EVV-Gly-OH, and Boc-Gly-EFF-OH), were studied by ‘H NMR measurements and molecular mechanics calculations (1). The molecular structures of Boc-Gly-EVV-OH, Boc-Gly-EFF-OH, and the hydrochloride of EVV-OCH₃ were determined by X-ray analyses. The conformations of the piperazinone rings and the side chains of these oligopeptides were clarified.     

Analogs of Substance P modified at the C‐terminus which are both agonist and antagonist of the NK‐1 receptor depending on the second messenger pathway

Abstract: The initial goal of this study was to analyze, using photolabeling, the interactions between Substance P and its tachykinin NK‐1 receptor. Therefore, the photoreactive amino acid para‐benzoyl‐phenylalanine (pBzl)Phe was incorporated into the Substance P sequence from position 4 to 11 leading to Bapa⁰[(pBzl)Phe^x]SP analogs. Biotinyl sulfone‐5‐aminopentanoic acid (Bapa) was introduced in order to purify the covalent complex. These photoreactive SP analogs were first assayed for their affinity for the two binding sites associated with the NK‐1 receptor, as well as for their potency in activating the phospholipase C and adenylate cyclase pathways. All analogs photoreactive from position 4 to 11 have moderate to high affinity for the two NK‐1 receptor‐binding sites, except for the analog modified at position 7. This affinity could be correlated to their potency to activate the phospholipase C and adenylate cyclase pathways, except for the analog photoreactive at position 11. Bapa⁰[(pBzl)Phe¹¹]SP was found to be an agonist in the phospholipase C pathway and an antagonist in the adenylate cyclase pathway, other analogs modified at position 11 were therefore analyzed. Among these, Bapa⁰[Pro⁹, (pBzl)Hcy(O₂)¹¹]SP is a partial agonist, whereas Bapa⁰[Hcy(ethylaminodansyl)¹¹]SP is a full agonist in the phospholipase C pathway, the two analogs being antagonist in the adenylate cyclase pathway. These results show that analogs of SP can be simultaneously agonist at one binding site and antagonist at the other binding site associated with the NK‐1 receptor.