反相高效液相色谱法测定人肌腱中的胶原蛋白

建立了测定人肌腱中胶原蛋白含量的高效液相色谱法。动物肌腱中的胶原蛋白经酸水解后生成包括羟脯氨酸在内的氨基酸混合物,用2,4-二硝基氯苯对水解产物衍生化,然后以0.01 mol/L乙酸钠-乙酸缓冲液(pH 6.0)-乙腈(体积比为80∶20)为流动相,经反相C18柱分离,紫外检测器于360 nm波长处检测来测定羟脯氨酸的含量。羟脯氨酸是胶原蛋白的特异性氨基酸且含量稳定,因而可通过样品中羟脯氨酸的含量来计算胶原蛋白的含量。该方法对羟脯氨酸的检出限为3 μg/L,羟脯氨酸为3 μg/L~100 mg/L时与峰面积的线性关系良好;样品测定的相对标准偏差为1.95%,加标回收率为98.4%~110.8%。对60份人肌腱样品中胶原蛋白的含量进行了测定。所建立的方法灵敏、准确、干扰少,适用于肌腱中胶原蛋白含量的测定。     

毛细管电泳-激光诱导荧光检测肌腱和肌腱细胞中的羟脯氨酸

建立毛细管电泳-激光诱导荧光检测(CE-LIF)分析羟脯氨酸的方法。肌腱和肌腱细胞中的胶原蛋白碱水解生成氨基酸,经异硫氰酸荧光素(FITC)衍生,采用LIF-CE分离测定胶原蛋白特异性氨基酸-羟脯氨酸。羟脯氨酸在0.5μg/L~8×103μg/L浓度范围内线性关系良好;检出限为0.5μg/L。相对迁移率和相对峰高的相对标准偏差(RSD)分别为5.0%和6.1%。测定了60份肌腱和9份细胞样品,加标回收率为95%~110%。将所建立的毛细管电泳方法与高效液相色谱法(HPLC)进行比较,两者测定结果相对误差为-1.9%~2.0%。本法仅需一次荧光标记,操作简单、快速灵敏,12min内完成一个分析周期,适于测定肌腱和细胞样品。     

高效液相色谱-质谱联用测定胶原蛋白中的羟脯氨酸

建立了一种简单、快速地测定胶原蛋白中羟脯氨酸(HYP)的高效液相色谱-电喷雾质谱(HPLC-ESI/MS)方法。胶原蛋白经酸水解后,以乙腈-0.05%的三氟乙酸水溶液(体积比为5∶95)为流动相,以1.0 mL/min的流速在C8反相柱上进行分离。以茶氨酸为内标,利用质谱定性定量测定HYP。在电喷雾正离子模式下,对m/z 132和m/z 175离子进行选择离子监测。在11.7～117 mg/L范围内,HYP与内标物茶氨酸的峰面积比和HYP的质量浓度呈良好的线性关系,相关系数为0.9993。含量测定的相对标准偏差为1.87%,回收率为97.85%～101.76%。此方法流动相简单,分析时间短且无需衍生处理,抗干扰能力强,能准确快速地测定胶原蛋白中HYP的含量。     

柱前衍生高效液相色谱法测定肝纤维化兔给药后尿羟脯氨酸含量

建立了一种快速测定羟脯氨酸的反相高效液相色谱法(RP-HPLC),并测定了血吸虫病肝纤维化兔给药中药复方口服液(HDS)前后尿液中羟脯氨酸含量变化。采用9-芴基甲氧基羰酰氯(FMOC)为衍生试剂,以3,4-脱羟脯氨酸为内标,在Zorbax SB-C18柱上用甲醇和醋酸钠缓冲溶液为流动相进行梯度洗脱,二极管阵列检测器(DAD)262nm处检测。羟脯氨酸在5.0~200μmol/L浓度范围内呈良好线性相关系(r=0.9999),方法检出限为2.0μmol/L(S/N=3),回收率为96.5%~99.0%。本方法具有样品处理步骤简单、准确度高、重现性好、分离时间短等优点,适合大批量样品测定。     

血浆游离氨基酸的柱前衍生反相高效液相色谱分析及其在临床检测中的应用

用邻苯二甲醛(OPA)-9-芴基甲氧基羰酰氯(FMOC)柱前衍生反相高效液相色谱法测定了婴幼儿血浆中的游离氨基酸。衍生由自动进样器在线自动完成;氨基酸的衍生物用Hypersil ODS反相柱分离,荧光检测器检测;流动相A为10 mmol.L-1pH 7.2的磷酸盐溶液(PB),含0.5%(φ)四氢呋喃;流动相B为PB-甲醇-乙腈(体积比50∶35∶15);用二元线性梯度程序洗脱,0 min时A为100%,B为0%;25 min时A为0%,B为100%。本法在25 min内使22种氨基酸全部得到良好分离,分离度大于1.5,最小检出限为1 nmol.mL-1,在20~300 nmol.mL-1浓度范围内,22种氨基酸的峰面积和浓度之间的线性相关系数在0.982~0.999之间,保留时间和峰面积的相对标准偏差分别为0.05%~0.50%和0.7%~2.9%,回收率为98%~101%。用本法在医院送检的血浆样品中检出了高甘氨酸血症、苯丙酮尿症、精氨琥珀酸血症、胍氨酸血症、同型半胱氨酸尿症、枫糖尿症和酪氨酸血症等氨基酸遗传代谢缺陷症。     

邻苯二甲醛柱前衍生反相高效液相色谱法测定人和小鼠血浆中的游 …

以邻苯二甲醛（ＯＰＡ）３－巯基丙酸（３－ＭＰＡ）为衍生试剂，手动柱前衍生，ＯＤＳ（十八基哇烷）柱分离；以磷酸盐缓冲液（ＰＨ７．２）配制流动相，二元一级性梯度洗脱，紫外３４０ｎｍ检测，在４０ｍｉｎ内分离测定了人和小鼠血浆中２１种游离氨基酸的含量。方法准确可靠。２１种氨基酸保留时间和峰面积的相对标准偏差分别为０．０９－０．３８％和１．５－４．９％，氨基酸的进样量为０．１－１．６ｎｍｏｌ时，峰面积与进样     

柱前衍生反相高效液相色谱法测定小麦中氨基酸含量

以肌氨酸为内标物,邻苯二甲醛-9-芴甲基氯甲酸酯为柱前衍生剂,用ODS色谱柱在柱温40℃下,采用二元梯度洗脱,DAD检测器在338nm波长处检测,建立了一种利用反相高效液相色谱同时测定小麦籽粒中17种氨基酸的方法。氨基酸浓度在5～800μmol／L范围内,其峰面积与内标物峰面积的比值和氨基酸浓度的线性相关系数均大于0．996;17种氨基酸的加标回收率在97．5％～103．1％范围内。应用本方法对小麦籽粒中氨基酸含量进行测定,取得了较理想的结果。同时,本法还可应用于糙米和玉米等粮食中氨基酸含量的测定。     

HPLC法在线衍生测定中华绒螯蟹中17种氨基酸含量

建立了中华绒螯蟹中17种氨基酸同时测定的反相高效液相色谱法。样品用HCl溶液在110℃水解24 h,水解液用NaOH溶液中和,以邻苯二甲醛(OPA)和9-芴甲基氯甲酸酯(FMOC)为柱前衍生化试剂,采用3,3’-2硫代-2丙酸(DTDPA)将水解液中半胱氨酸氧化为S-2-羧乙基硫代半胱氨酸(Cys-MPA),实现对半胱氨酸的保护。采用AdvanceBio AAA氨基酸专用色谱柱进行分离,以Na_2B_4O_7、Na_2HPO_4缓冲液与乙腈、甲醇为流动相,在线衍生进样、梯度洗脱,紫外检测器检测,外标法定量。结果表明:17种氨基酸在1～200μg/mL的范围内与各自峰面积呈良好的线性关系,其线性相关系数(R~2)在0.9973～1.0000之间,检测限为0.12～0.30μg/mL;在2.30,4.60,6.90 mg/g 3个加标浓度下的平均加标回收率在82.6%～115.2%之间,相对标准偏差(RSDs)为0.7%～4.8%。该方法实现了同时对中华绒螯蟹中半胱氨酸以及其他一级、二级氨基酸的准确定量。     

FMOC柱前衍生法测定鱼皮胶原肽中羟脯氨酸的含量

建立了FMOC柱前衍生液高效液相色谱法测定鱼皮胶原肽中羟脯氨酸含量的分析方法。使用芴甲基氯甲酸酯(FMOC-Cl)作为衍生试剂对鱼皮胶原肽水解液进行衍生,采用Venusil MP C18(4.6 mm×250 mm,5μm)色谱柱,以乙酸盐缓冲液与乙腈为流动相进行梯度洗脱,荧光检测器激发波长250 nm,发射波长395 nm下外标法定量。所测羟脯氨酸的线性关系良好,检出限为0.03μg/m L,平均回收率在97.7%~99.9%之间,相对标准偏差为2.0%(n=6)。     

柱前衍生-高效液相色谱法测定鱼类中组胺

建立测定鱼类中组胺含量的柱前衍生-高效液相色谱（HPLC）联合紫外检测分析方法。样品均质后先用三氯乙酸水溶液震荡超声提取,再用丹磺酰氯衍生,采用HPLC-紫外检测器在254 nm处对组胺衍生物进行检测,以色谱峰面积外标法定量。组胺的质量浓度在1.0～50.0μg/mL范围内与色谱峰面积线性关系良好,相关系数为0.999 7,方法检出限为7.2μg/kg,定量限为24μg/kg。样品加标回收率为96.8%～99.2%,测定结果的相对标准偏差为1.6%～3.7%(n=6)。该方法快速准确、灵敏度高、重复性好,可用于鱼类产品中组胺的定量分析。     

Determination of hydroxyproline in tissues and the evaluation of the collagen content of the tissues

The concentrations of hydroxyproline (an amino acid specific of collagen) in a number of connective tissues were determined. Two procedures were compared. In one of them, amino acids were preseparated by chromatography and then determined on a standard amino acid analyzer. In the other procedure, hydroxyproline was selectively oxidized without amino acid separation and determined by a spectrophotometric reaction with Ehrlich’s reagent. Data obtained for purified collagen preparations in accordance with the two procedures were consistent with each other. The results can be somewhat different in unpurified preparations and tissues because of the presence of polysaccharide components in the tissues.     

Hydroxyproline quantification for the estimation of collagen in tissue using multiple reaction monitoring mass spectrometry

Collagens are highly abundant mammalian proteins that contain a high content of hydroxylated amino acids such as hydroxyproline. We have exploited the high hydroxyproline content of collagen and developed a method for hydroxyproline quantification as a measure of collagen content in muscle samples. The novel method utilizes a highly selective and sensitive method of multiple reaction monitoring (MRM) by mass spectrometry. The analytical method is simple, rapid (5min), convenient (no derivatization), precise (<17% RSD), accurate (90-108%), sensitive (4.88nmol/L) and linear (R(2)>0.999) over three orders of magnitude (5-5000nmol/L).     

Kinetics of biomethanation of solid tannery waste and the concept of interactive metabolic control

Anaerobic digestion of calf skin collagenous waste was optimized for a batch process based on accelerated maximal methane yield per gram of input volatile solid. A kinetic analysis with respect to changes in the levels of volatile solid, collagen, amino sugars, amino acids, hydroxyproline, ammonium ions, and volatile fatty acid were followed for a period of 80 d. Distinct metabolic phases included an initial high rate collagenolysis for 4 d, with 50% degradation and was followed by an acidogenic phase between 4–12 d with voltatile fatty acids levels increasing to 215 mmol/L. Subsequently methanogenesis ensued and was maximal between 12–24 d when volatile fatty acids attained steady state levels. During the period of 80 d, the overall decrease in volatile solid level was 65%, whereas the collagen level declined by 85% with 0.45 L of methane yield/g of volatile solid degraded. Based on the levels of various metabolites detected, the concept of interactive metabolic control earlier proposed has been validated.     

Hydroxyproline Measurement by High Performance Liquid Chromatography: An Improved Method of Derivatization

Abstract

Hydroxyproline is a postsynthetic derivative of proline which is commonly used to estimate the collagen content of tissues. Values (weight %) of hydroxyproline range from ten to twenty percent in most collagen types, with Type I having 11.4 percent hydroxyproline. This fact is useful for estimating the collagen content in various acid hydrolyzed tissue samples. In this paper, the authors describe a technique which produces linear hydrolysis of collagen coupled with a sensitive ultraviolet detection scheme for the 9-Fluorenylmethoxycarbonyl Chloride(FMOC-Cl) derivative of hydroxyproline. The separation itself employs reverse phase chromatography with a sensitivity of approximately 0.12 nmoles of hydroxyproline or 0.14 μg Type I collagen.     

ANALYSIS of Acid-Soluble Hydroxy-Proline,Free Proline and Collagen-Bound Hydroxyproline in Rat Liver by High Performance Liquid Chromatography With Pre-Column Derivatization

Abstract

A High Performance Liquid Chromatographic analysis of acid-soluble hydroxyproline, free proline and collagen-bound hydroxyproline from rat liver is described. A pre-column derivatisation with the fluorogenic reagent 7-chloro-4-nitrobenz-2-oxa-1,3-diazole was adopted. The Chromatographic assay was performed by using a Spherisorb ODS2 reversed phase column, with fluorometric detection. Elution was carried out isocratically with acetonitrile-O. 1 M sodium phosphate buffer, pH 7.2 (9:91, v/v). The derivatives of standard imino acids and of internal standard (3,4-dehydro-L-proline) can be separated in less than 15 min and quantitated with high sensitivity (1 injected pmole of hydroxyproline and 5 injected pinoles of proline). Key steps in the approach with the biological sample include initial extraction of acid-soluble hydroxyproline, free proline and collagen; acid hydrolysis of collagen and of hydroxyproline-containing peptides; selective derivatisation of imino acids with the fluoro-genic reagent, after a previous reaction of the sample with o-phthalaldehyde; finally, chromatographic analysis of the derivatives. The assay of acid-soluble hydroxyproline requires a clean-up step on a Sep-Pak C₁₈ cartridge prior to the analytical chromatography. Owing to its high sensitivity and reliability, the presented procedure can be used in studies on collagen metabolism and it should be preferred over the time-consuming and less sensitive colorimetric assays previously described.     

Determination of 4‐hydroxyproline‐2‐epimerase activity by capillary electrophoresis: A stereoselective platform for inhibitor screening of amino acid isomerases

Isomerases involved in the metabolism of D /L ‐amino acids represent promising therapeutic targets for treatment of disease. Herein, we report a tunable platform for the assessment of enzymatic kinetics involving amino acid isomerization by CE that offers improved selectivity and sensitivity over traditional methods. Enzyme activity and competition assays were evaluated for various hydroxyproline diastereoisomers, proline enantiomers and their structural analogs using 4‐hydroxyproline‐2‐epimerase as a model system. In this work, pyrrole 2‐carboxylic acid was found to be a selective inhibitor of 4‐hydroxyproline‐2‐epimerase with a half‐maximal inhibition concentration of (2.3±0.1) mM. Reliable methods for unambiguous characterization of amino acid isomerases are required for the screening of novel inhibitors with epimerase and/or racemase activity.     

Microderivatization of 4-[18O]hydroxyproline and quantitation with a benchtop mass spectrometer

Accurate estimation of in vivo turnover rates of collagen is complicated by amino acid reutilization. It was previously shown that the ideal, non-recycling tracer was [18O]hydroxyproline synthesized in vivo. The analytical method for measuring turnover rates with [18O]hydroxyproline must include analyte quantitation for pool size determination and isotope ratio measurement for determining levels of label incorporation. For ease of use and widest availability, a benchtop gas chromatograph-mass spectrometer in the electron-impact ionization mode was chosen. Here we present a versatile procedure for hydroxyproline derivatization that is well suited for routine, large-scale determination of analyte concentrations and relative levels of 18O incorporation.     

The mutual influence of imino acids and phenylalanine on the dynamic characteristics of sorption on KU-2 × 8 sulfocation exchanger in the H form

The dynamics of sorption of pure imino acids (proline and hydroxyproline) and imino acids in the presence of aromatic amino acid, phenylalanine, on KU-2 × 8 sulfocation exchanger in the H form was studied. Mutual influence of amino acids on the dynamic characteristics of sorption was observed. This influence changed the shape of elution curves and decreased the working exchange capacity. Both competitive and synergistic sorption mechanisms governed sorption of amino acids from binary solutions.     

Surprisingly high stability of collagen ABC heterotrimer: evaluation of side chain charge pairs

Type I collagen is a major component of skin, tendon, and ligament and forms more than 90% of bone mass. It is an AAB heterotrimer assembled from two identical alpha1 and one alpha2 chains. However, the majority of studies on the effects of amino acid substitution on triple helix stability have been performed on collagen homotrimeric helices. In a homotrimer, it is impossible to determine whether the contribution to stability is from the polyproline II helix propensity of the amino acids or from interhelix amino acid interactions. The presence of amino acids in all three chains further exaggerates their contribution. In contrast, in a heterotrimer, the individual chains may be tailored in order to have the substitution in one, two, or all three chains. Therefore, a heterotrimer can divulge specific information about any interaction based upon the substitutions in individual chains. In this paper, we evaluate the contribution of electrostatic interactions between side chain charge pairs on the stability of heterotrimers. We synthesize and analyze the stability of four AAB and four ABC heterotrimers including a surprisingly stable ABC heterotrimer composed of (DOG)10, (PKG)10, and (POG)10 chains (O = hydroxyproline). This heterotrimer has a stability comparable to that of a (POG)10 homotrimer even though D and K occur 20 times in the heterotrimeric helix and have been previously shown to significantly destabilize the triple helix compared to the P and O imino acids. These results show that the stability of heterotrimers cannot be directly determined from the analysis of charge pairs in homotrimers. Because collagen heterotrimers can be designed to have substitution in one, two, or three chains, it gives us the ability to decode cross-strand interactions in collagen in a similar fashion to alpha-helical coiled-coil interactions and DNA duplex hydrogen bonding.