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Results for “Hydroxyproline”

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PubMed1992

The amino acid sequence of a type I copper protein with an unusual serine- and hydroxyproline-rich C-terminal domain isolated from cucumber peelings.

We have determined the amino acid sequence of a small copper protein isolated from cucumber peelings. This cupredoxin contains 137 amino acids including a pyroglutamate as the first residue. The N-terminal 110 amino acid-long domain shows 30-37% identity to 2 other cupredoxins, stellacyanin and cucumber basic blue protein. A unique feature of this protein is a 27 amino acid-long C-terminal domain rich in 4-hydroxyproline and serine and resembling certain plant cell wall proteins. The prolines in this domain are hydroxylated to a different extent depending on the surrounding sequence.

Amino Acid Sequence↗
PubMed1982

Isolation of proline and hydroxyproline from fossil bone.

We describe a simple and rapid procedure for the isolation of proline and hydroxyproline from fossil bone based on the isolation of gelatin, hydrolysis, purification with XAD-2, deamination of primary amino acids with aqua regia, and separation of the imino acids by cation exchange chromatography. This procedure will provide material for accurate bone carbon dating, and stable carbon isotope ratio determinations for the evaluation of paleodiets.

Animals↗
PubMed1975

Metabolic effects of propranolol in thyrotoxicosis. I. Nitrogen, calcium, and hydroxyproline.

The effect of propranolol on the hypermetabolism of thyrotoxicosis was investigated in eight subjects with diffuse toxic goiter. After equilibration on a constant nitrogen, calcium, and hydroxproline intake, nitrogen balance was determined before and during propranolol therapy prior to subtotal thyroidectomy and compared to similar data obtained in seven of the patients following surgically induced euthyroidism. Propranolol administration was associated with clinical amelioration and a rapid, statistically significant, improvement in nitrogen retention. A slight additional improvement in retention was noted in the postoperative euthyroid state. Oxygen consumption, measured serially in four patients, was not significantly changed by propranolol. Urinary loss of calcium, phosphorus, and hydroxyproline was unaffected by propranolol, but excretion of these substances was sharply reduced in the subjects restudied postoperatively. These data offer a evidence of a previously unreported nitrogen sparing effect of oral propranolol during its short-term administration in thyrotoxic man.

Adult↗
PubMed1975

Colchicine: effects upon urinary hydroxyproline excretion in patients with scleroderma.

Three patients with scleroderma were given intravenous infusions of colchicine (2-4 mg/day) for 3 days. Twenty-four-hour urine collections were assayed for total hydroxyproline (HYPRO), an index of collagen resorption, and for nondialyzable polypeptide HYPRO, an index of collagen synthesis. During the colchicine infusions there was a fall in total urinary HYPRO and a slight increase in the per cent nondialyzalbe HYPRO in each patient. The hydroxylysyl-galactosyl-glucose (HGG) to hydroxylysyl-galactose (HG) ratios were not strikingly different in two samples, with the greastest differences in HYPRO excretion. Our results suggested that total body collagen catabolism had diminished without a concomitant decrease in synthesis. In contrast to provocative reports in the literature, these data do not support the hypothesis that administration of colchicine in doses tolerated in man can either inhibit synthesis of new collagen, increase degradation of mature collagen, or be of use in treatment of fibrotic states.

Adult↗
PubMed1984

Reduction by propranolol of urinary hydroxyproline excretion in human hyperthyroidism: a beta-receptor blockade effect or a membrane stabilizing mechanism?

In order to investigate the mechanism whereby oral propranolol administration reduces the increased rate of urinary hydroxyproline excretion (UHxE) of patients with hyperthyroidism, a comparison was made of the effects of the oral administration of propranolol-timolol, propylthiouracil (PTU), and a placebo to patients with hyperthyroidism and to normal controls. Propranolol decreased the pulse rate (P less than 0.01), serum triiodothyronine (T3) level (P less than 0.05), and UHxE (P less than 0.01) without modifying the serum free thyroxine index (FT4I) or parathormone (PTH) level. Timolol decreased the pulse rate (P less than 0.01) to the same extent as propranolol, had no effect on T3, FT4I, or PTH, and failed to decrease UHxE. Administration of PTU decreased the T3 level (P less than 0.05) to a similar extent as propranolol without modifying the FT4I or PTH level and had no effect on UHxE. Placebo administration had no effect. These results suggest that the reduction of UHxE by propranolol is not due to the beta-receptor-blocking properties of propranolol nor mediated by the propranolol-induced decrease in the level of T3 but is probably due to the membrane-stabilizing properties of propranolol.

Adult↗
PubMed1993

Frog prodermorphin expressed in mammalian cells is partly converted to the hydroxyproline containing precursor.

Using recombinant vaccinia virus, we have expressed in mammalian cells the cDNA coding for the precursor of dermorphin, a D-alanine containing opioid peptide from the skin of the South American frog Phyllomedusa sauvagei. HeLa cells and AtT-20 cells produced prodermorphin where proline-6 of dermorphin was partly hydroxylated. This was demonstrated by digesting the partially purified precursors with trypsin and carboxypeptidase B. After immunoprecipitation and separation by HPLC, two decapeptides were detected which differed by the presence of proline or hydroxy-proline at position 6. This demonstrates that HeLa cells as well as AtT-20 cells can perform the post-translational conversion of certain proline residues to hydroxyproline in a foreign hormone precursor expressed in these cells.

Amino Acid Sequence↗
PubMed1986

Effect of mast cell stimulators or inhibitors on plasma lipids and aortic content of lipids, hexosamine and hydroxyproline in rats.

Twenty-one-day-old rats were treated with mast cell stimulators or inhibitors. Mast cell inhibition produced decrease of total cholesterol in plasma and aorta, while the stimulation led to an increase. Both stimulation and inhibition produced increased levels of plasma and aorta triglycerides, and decrease of aorta content of hexosamine, hydroxyproline and total protein; these same effects could be due to different release of specific mast cell mediators.

Animals↗
PubMed1993

Micellar electrokinetic chromatography of hydroxyproline and other secondary amino acids in biological samples with laser-induced fluorescence detection.

Micellar electrokinetic chromatography (MEKC) with laser-induced fluorescence (LIF) was used for the rapid and sensitive detection of hydroxyproline in serum and hydrolyzed urine that were pre-column derivatized with 9-fluorenylmethyl chloroformate (FMOC). The application of the combined o-phthalaldehyde (OPA)/FMOC derivatization in MEKC for the selective detection of secondary amino acids in biological samples is investigated.

Amino Acids↗
PubMed1995

Rapid reversed-phase high-performance liquid chromatographic method with double derivatization for the assay of urinary hydroxyproline.

An HPLC method with two derivatizations, the first with o-phthaldehyde in order to eliminate interferences due to some primary amino acids eluting with retention times similar to those of hydroxyproline and the second with dabsyl chloride, was developed and evaluated. Calibration graph linearity, influence of agitation and temperature on the preparation of the first derivative and the influence of the detection wavelength were assessed. The analysis time is shorter in comparison with other available methods, and therefore this method is suitable for laboratories that analyse both small and large series of samples.

Chromatography, High Pressure Liquid↗
PubMed1988

Triiodothyronine stimulates urinary excretion of calcium and hydroxyproline in autosomal dominant osteopetrosis.

Six patients with autosomal dominant osteopetrosis were treated orally with 100 mcg. triiodothyronine (T3) daily for seven days. The effect of T3 on bone remodelling was monitored. T3 treatment increased serum T3 from day 1 to 7 (p less than 0.02) with a corresponding fall in serum T4 (p less than 0.01) and serum TSH (p less than 0.02). The levels of thyroid hormones returned to initial levels within the observation period. The renal excretion of calcium and hydroxyproline increased significantly (p less than 0.05) on day 7 and 14 respectively, while there was no significant increase in phosphate excretion. No significant changes were observed in serum calcium, phosphate, or osteocalcin during the study. The observed changes suggest that bone resorption in autosomal dominant osteopetrosis is stimulated by exogenous administration of T3.

Adult↗
PubMed1989

Rapid determination of total hydroxyproline (HYP) in human urine by HPLC analysis of the phenylisothiocyonate (PITC)-derivative.

A recent development in the preparation for amino acid analysis is the use of phenylisothiocyanate (PITC) as a precolumn derivatizing agent prior to analysis to form a stable derivative. These derivatives can then be separated by reversed phase high pressure liquid chromatography (HPLC). Because of interest in the accurate measurement of urinary hydroxyproline (HYP), PITC was used for derivatization followed by HPLC analysis. Using an automated computer-controlled sampler system, up to 75 samples can be analyzed each 24 h. Technical details, specificity, and reliability of this method are provided. Duplicate measurements of HYP had a coefficient of variation (CV) of 5.5% and with a recovery of HYP in spiked urine samples of 94 to 104%. A sample frozen and thawed 10 times showed no change in the concentration of HYP. When total HYP was measured in 230 healthy women between 20 and 39 years of age, it was found to be 236.62 +/- 146.41 mumoles/L. These samples were researched in 3.5 days using this technique.

Adult↗
PubMed2005

Quantification of hydroxyproline in small amounts of skin tissue using isocratic high performance liquid chromatography with NBD-F as fluorogenic reagent.

In order to determine the collagen content of small amounts of skin tissue, we developed a new, simple and highly sensitive method of measuring the quantity of hydroxyproline (Hyp) using isocratic high performance liquid chromatography (HPLC) with a fluorogenic agent, 7-fluoro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-F). The recovery rate of Hyp and reproducibility of the assay were high, and the test was sensitive enough to detect Hyp in less than 1 mg of skin tissue. This method is clinically useful for ensuring accurate diagnosis and for monitoring specific skin conditions using small human skin samples collected in biopsies.

4-Chloro-7-nitrobenzofurazan↗
PubMed1980

Automated triple assay for proline, hydroxyproline and hydroxylysine on one single sample.

1. A new, quick, sensitive and specific assay for the quantitative determination of proline is presented together with its automatization. The use of glacial acetic acid-formaldehyde as the solvent for ninhydrin lends a series of advantages to the reaction. 2. A serial automated procedure for the simultaneous detection of proline, hydroxyproline and hydroxylysine in one single sample is pesented. The advantage of the triple assay lies in the use of one single sample instead of three previously aliquoted fractions in three individual automated assays. The triple assay is as specific, reproducible and sensitive as the individual assays. 3. A quick, manual assay for hydroxylysine is presented. This method represents a further simplifiction of previous ones by the same author and adds the advantage of rapidity to their sensitivity and specificity.

Adolescent↗
PubMed1986

Improved high-performance liquid chromatography method for quantitation of proline and hydroxyproline in biological materials.

Numerous high-performance liquid chromatography systems have been described for the determination of hydroxyproline (Hyp) and proline (Pro) levels in biological materials. These methods are generally complicated and have shortcomings in applicability due to poor separation, low sensitivity or derivatization-associated problems. The large number of chemical components present in biological samples further complicates the analysis of Hyp which usually occurs in extremely low concentrations. The present investigation describes the development of a simple highly sensitive derivatization method which results in good separation of peaks and which is capable of quantitating less than 10 pmol of Hyp and Pro in complex test systems. The method is based on removal of o-phthalaldehyde (OPA) derivatives of primary amino acids using reversed-phase chromatography, pre-column derivatization with OPA and phenylisothiocyanate, and detection of derivatized Hyp and Pro using a UV detection system. The procedure yields good peaks and a 93% recovery of Hyp and Pro provided that the analysis is initiated within 5 min of completion of OPA derivatization. While a 93% recovery of Pro was obtained up to 100 min post-derivatization with OPA, the recovery of Hyp is decreased to approximately 80% within the same time interval.

Amino Acids↗
PubMed1985

Reversed-phase high-performance liquid chromatographic separation and quantitation of phenylthiohydantoin derivatives of 25 amino acids, including those of cysteic acid, 4-hydroxyproline, methionine sulfone, S-carboxymethylcysteine and S-methylcysteine.

A high-performance liquid chromatography system is presented which allows separation and quantitation (in the range 4-1000 pmol) of all common phenylthiohydantoin amino acids, including derivatives of 4-hydroxyproline, methionine sulfone and three differently modified forms of cysteine. By showing the actual solvent gradient during elution (as opposed to the programmed gradient) and by supplying information on the effects of minor changes in solvent-pH, column temperature, flow-rate, and concentration of 2-propanol in the gradient, we make guidelines available for fine-tuning the separation with new Ultrasphere-ODS (C18) columns.

Amino Acids↗
PubMed1993

Determination of the urinary D/L trans-3-hydroxyproline ratio: a noninvasive screening test for Alport syndrome.

Because disturbed conformation of connective tissue proteins can be accompanied by increased racemization (i.e., an increased ratio of dextrorotatory (D) to levorotatory (L) amino acid molecules), we studied by high-performance liquid chromatography the renal excretion of the D-form of the basement membrane-specific trans-3-hydroxyproline in patients with Alport syndrome. The D/L ratio was significantly higher in patients with Alport syndrome than in patients with other renal diseases or in healthy control subjects. We therefore suggest that this factor may be a simple noninvasive (screening) test for Alport syndrome.

Adolescent↗
PubMed1975

Serum alkaline phosphatase and urinary hydroxyproline values in children receiving phenobarbital with and without vitamin D.

Concentrations of serum alkaline phosphatase and total urinary hydroxyproline were measured in 36 children to study the effect of phenobarbital administration with respect to the development of rickets in patients receiving anticonvulsive medications over prolonged periods of time. Administration of phenobarbital led to the appearance of increased AP and HOP values very early in the course of treatment and without any obvious bone changes suggestive of rickets; a single large oral dose of vitamin D had no appreciable effects in restoring the biochemical derangement. On the other hand, the administration of vitamin D in a daily dose of 4,000 IU for a period of two months hampered the appearance, or restored already existing changes of latent rickets, in children receiving anticonvulsive medication. The results in the present study favor the concept that phenobarbital administration is implicated in the development of rickets. The need for simultaneous daily administration of supplements of vitamin D in subjects receiving anticonvulsive drugs is stressed.

Adolescent↗
PubMed2006

Detection of cytoplasmic glycosylation associated with hydroxyproline.

A special class of glycosylation occurs on a proline residue of the cytoplasmic/nuclear protein Skp1 in the social amoeba Dictyostelium. For this glycosylation to occur, the proline must first be hydroxylated by the action of a soluble prolyl 4-hydroxylase acting on the protein. Cytoplasmic prolyl 4-hydroxylases are dioxygen-dependent enzymes that have low affinity for their O2 substrate and, therefore, have been implicated in O2-sensing in Dictyostelium, as well as in vertebrates and invertebrates. The sugar-hydroxyproline linkage has low abundance, is resistant to alkali cleavage and known glycosidases, and does not bind known lectins. However, initial screens for this modification can be made by assessing changes in electrophoretic mobility of candidate proteins after treatment of cells with prolyl hydroxylase inhibitors, and/or by metabolic labeling with [3H]sugar precursors. In addition, cytoplasmic hydroxylation/glycosylation can be assessed by assaying for cytoplasmic glycosyltransferases. Here we describe these methods and examples of their use in analyzing Skp1 glycosylation in Dictyostelium and the apicomplexan Toxoplasma gondii, the causative agent of toxoplasmosis in humans.

Animals↗