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PubMed1969

Synthesis and secretion of hydroxyproline containing macromolecules in carrots. I. Kinetic analysis.

When disks of carrot (Daucus carota) phloem parenchyma are incubated for 6 days there is a 10-fold increase in cell wall hydroxyproline due to the synthesis and secretion of hydroxyproline-containing macromolecules. The synthesis of these molecules and their secretion are demonstrated by measuring the kinetics of incorporation and of chase of (14)C-proline and hydroxyproline in different fractions of the cytoplasm and the cell wall. The hydroxyproline-containing molecules which are secreted are associated with the membranous organelles of the cytoplasm. They can be fractionated into trichloroacetic acid-soluble and trichloroacetic acid-precipitated fractions. The properties of the trichloroacetic acid-soluble fraction associated with the membranous organelles are consistent with its role as a cell wall precursor.

Journal Article↗

PubMed1970

Synthesis and Transport of Hydroxyproline-rich Components in Suspension Cultures of Sycamore-Maple Cells.

Plant cell walls contain a glycoprotein rich in hydroxyproline. To determine how Acer pseudoplatanus L. cells transport this glycoprotein to the wall, the pulse-chase technique was used to follow changes in specific radio-activity of hydroxyproline and proline in isolated, mitochondrial, Golgi, microsomal, soluble protein, and wall fractions. The turnover rates or changes in specific radioactivity of cytoplasmic hydroxyproline in these cell fractions indicated that the bulk of this hydroxyproline was transferred not by the Golgi apparatus but by a smooth membranous component.

Journal Article↗

PubMed1971

Effect of indoleacetic Acid and hydroxyproline on isoenzymes of peroxidase in wheat coleoptiles.

Indoleacetic acid at 0.017 millimolar inhibited the formation of three peroxidase isoenzymes in both soluble and wall-bound enzyme fractions of wheat coleoptile (Triticum vulgare) tissue. Hydroxyproline at 1 millimolar prevented the indoleacetic acid-induced inhibition. Indoleacetic acid oxidase activity in the soluble fraction was decreased by indoleacetic acid and was restored by hydroxyproline. Most of the indoleacetic acid oxidase activity was located in the electrophoretic zones occupied by two of the peroxidase isoenzymes influenced by indoleacetic acid and hydroxyproline. At least part of the effect of hydroxyproline on auxin-induced elongation of coleoptile tissue may be through control of auxin levels by indoleacetic acid oxidase.

Journal Article↗

PubMed1979

Cell Surfaces in Plant-Microorganism Interactions: II. Evidence for the Accumulation of Hydroxyproline-rich Glycoproteins in the Cell Wall of Diseased Plants as a Defense Mechanism.

Enrichment of the cell wall in hydroxyproline-rich glycoprotein is involved in the defense of muskmelon (Cucumis melo) seedlings to Colletotrichum lagenarium, the causative agent of anthracnose. The extent to which this accumulation proceeds may be experimentally modified by treating plants with ethylene or growing them in the presence of free l-trans-hydroxyproline. It appears that the increase in the wall hydroxyproline-rich glycoprotein mediated through ethylene is paralleled by an increasing resistance of the host to the pathogen. Inversely, inhibiting the synthesis of this glycoprotein in diseased plants is strictly correlated to an accelerated and more intense colonization of the host by the pathogen.In both cases, the inverse relationship between the accumulation of hydroxyproline-rich glycoproteins and the ability of the pathogen to develop in the host has been checked by the quantification, in infected tissues, of glucosamine, a characteristic component of chitin-containing fungi.

Journal Article↗

PubMed1980

Purification and Characterization of a Salt-extractable Hydroxyproline-rich Glycoprotein from Aerated Carrot Discs.

The salt-extractable hydroxyproline-rich glycoprotein (HRGP) of the cell wall of aerated carrot root discs has been studied by polyacrylamide gel electrophoresis. The predominant proline-labeled protein extractable from the cell wall is rich in hydroxyproline as shown by its specific loss of (3)H from proline labeled in position 4 and its shift in electrophoretic mobility after labeling in the presence of an inhibitor of hydroxyproline synthesis. Unlabeled HRGP can be identified by staining gels for carbohydrate. The HRGP has been purified by ion exchange chromatography and CsCl gradient centrifugation. The HRGP consists of about 50% protein and 50% carbohydrate with an overall molecular weight of 86,000. The amino acid composition of the protein portion consists of 50% hydroxyproline, 19% basic amino acids, 12% serine, and 10% tyrosine. This glycoprotein accumulates in a salt-extractable pool in the cell wall beginning between 10 and 20 hours of aeration and may also become incorporated into the nonextractable portion of the cell wall.

Journal Article↗

PubMed1982

Cell Surfaces in Plant-Microorganism Interactions : III. In Vivo Effect of Ethylene on Hydroxyproline-Rich Glycoprotein Accumulation in the Cell Wall of Diseased Plants.

Ethylene production and cell wall hydroxyproline-rich glycoprotein (HRGP) biosynthesis are greatly enhanced in melon (Cucumin melo cv. Cantaloup charentais) seedlings infected with Colletotrichum lagenarium. Short-term experiments performed in the presence of specific inhibitors of the ethylene pathway from methionine, namely l-canaline and amino-ethoxyvinylglycine, indicate that under non-toxic conditions, both ethylene and [(14)C]hydroxyproline deposition in the cell wall of infected tissues are significantly lowered. On the contrary, treatment of healthy tissues with 1-aminocyclopropane 1-carboxylic acid, a natural precursor of ethylene, stimulates both the production of the hormone and the incorporation of [(14)C]hydroxyproline into cell wall proteins.The data provide the first evidence of the in vivo effect of ethylene on the cell wall hydroxyproline-rich glycoprotein biosynthesis in plants.

Journal Article↗

PubMed1991

Biochemical and tissue print analyses of hydroxyproline-rich glycoproteins in cell walls of sporophytic maize tissues.

In an effort to understand the role of hydroxyproline-rich glycoproteins (HRGPs) in plant cell wall structure, we studied the distribution and physical properties of PC-1-like proteins (PC-1 being the major pericarp HRGP) throughout sporophytic tissues of two maize (Zea mays L.) varieties. We determined total amounts of hydroxyproline, an indicator of HRGPs, and did tissue print and Western blot analysis. We found hydroxyproline in cell walls of stems, leaves, roots, tassels, and silks. We also observed reactivity of anti-PC-1 monoclonal antibodies with anatomical prints of these tissues on nitrocellulose paper. Stem nodes and silks contained the most hydroxyproline and exhibited the strongest reaction with the antibody. PC-1 was localized in vascular bundles and the epidermis of stem tissue. However, localization to a specific cell type in the silk could not be determined at the resolution of the tissue print. The stem node protein had the same electrophoretic mobility as the pericarp protein as determined on Western blots prepared from cationic neutral gels. Protein extracts from silk tissues of both varieties studied contained one protein of the same size/charge as that found in pericarp, as well as some minor variant bands. The data presented here document that cell wall proteins are present in many tissues of the maize plant, although they are primarily in cell types contributing to support.

Journal Article↗

PubMed1995

Elicitors and suppressors of hydroxyproline-rich glycoprotein accumulation are solubilized from plant cell walls by endopolygalacturonase.

Treatment of bean cell walls with a pure endopolygalacturonase of the bean pathogen Colletotrichum lindemuthianum race beta released oligogalacturonides and pectic fragments which were separated according to their charge and size. Among galacturonic-acid-containing components, elicitors and suppressors of the plant cell wall hydroxyproline-rich glycoprotein (HRGP) were recovered. Two active small oligogalacturonides with degrees of polymerization of 2 and 3 were characterized by high-performance anion-exchange-chromatography pulsed amperometric detection and fast-atom-bombardment mass spectrometry; they elicited 40-70% hydroxyproline increase within 48 hours at 450 nmol/bean cutting. In contrast, pectic fragments of higher molecular mass, predominantly composed of galacturonic acid and containing sugars typical of the rhamnogalacturonan II domain of pectic polysaccharides, had the ability to substantially suppress hydroxyproline deposition. Maximum suppressor activity, 30-40% below the activity of the control, occurred in 48 hours. In view of the low one-cycle turnover of these proteins in the cell wall and of their structural role, these changes might significantly affect cell wall properties. Elicitation and/or suppression of hydroxyproline were correlated to modifications of HRGP-extensin gene expression. Northern-blot analysis of RNA showed that changes in the transcript intensity became clearly visible within the first 12 hours after the start of either treatment. The results show that pectic components of the plant extracellular matrix have the potential to regulate wall matrix biogenesis. Implications of this finding in plant defense and development are discussed.

Cell Wall↗

PubMed2000

Mass spectrometric analysis of hydroxyproline glycans.

Mass spectrometric techniques are presented which allow one to analyze the sugar part bound to hydroxyproline in hydroxyproline-rich glycoproteins. The hydroxyproline (Hyp) glycans obtained by alkaline hydrolysis give abundant [M + Na](+) ions by electrospray ionization which after collision-induced dissociation (CID) yield inter alia [Hyp - H + Na](+). In mixtures a parent ion scan of this species will indicate the various molecular species which can then be analyzed by MS(n) after CID in an ion trap, where successive losses of the sugar units are observed. Methylation techniques allow one to distinguish between linear and branched isomeric structures.

Animals↗

PubMed1996

Glycosylated threonine but not 4-hydroxyproline dominates the triple helix stabilizing positions in the sequence of a hydrothermal vent worm cuticle collagen.

The cuticle collagen of the vestimentiferan Riftia pachyptila, an organism which is endemic to deep-sea hydrothermal vents, has several unusual properties including an extraordinary length (1.5 microns), a high thermal stability (37 degrees C) in spite of a low 4-hydroxyproline content and an atypically high threonine content (20 mol%). We have now purified the constituent chain of cuticle collagen and show that it contains about 40% carbohydrate, which is mainly galactose, indicating that the chain has a molecular mass of approximately 750 kDa. Several large (30 to 150 kDa) fragments, which all contained carbohydrate, could be produced by cleavage with endoproteinase Lys-C, bacterial collagenase and cyanogen bromide (CNBr). Edman degradation of these and several smaller fragments was used to determine about 3000 sequence positions comprising 60% of the total triple-helical sequence. This demonstrated mainly typical Gly-X-Y triplet repeats with a few imperfections and a longer N-terminal non-triplet sequence. Most of the 4-hydroxyproline was found in triplet position X, where it decreases the stability of the triple helix. About 40% of the Y positions could not be identified, which correlated with a low abundance of threonine in the sequence and the demonstration of threonine in these positions after deglycosylation of several peptides by treatment with hydrofluoric acid. Matrix-assisted laser desorption ionisation mass spectrometry of selected peptides indicated that the blocked threonine residues are occupied by chains of one, two or three hexoses (presumably galactose). These glycosylated threonine residues in Y positions are therefore likely to replace 4-hydroxyproline as the major contributor to triple helix stabilization. Studies with a synthetic (Gly-Pro-Thr)10 oligopeptide demonstrated a low thermal stability of its triple helix which emphasizes a crucial role of glycosylation for stabilization.

Amino Acid Sequence↗

PubMed1977

[Determination of connective tissue content of meat products using the hydroxyproline methods (author's transl)].

The amino acids of collagenous and elastic connective tissue of beef and pork and of commercial meat products were determined by gaschromatography. A correlation was established between hydroxyproline and glycine and also between hydroxyproline and proline. Thus the content of elastic connective tissue in meat products is quite constant and compared with the amount of collagenous material insignificant.--Determination of amount of connective tissue in meat products from the amount of hydroxyproline this is suitable for the needs of food control.

Amino Acids↗

PubMed1999

Determination of the optical purity of threonine and hydroxyproline by capillary gas chromatography on a chiral stationary phase.

Experimental conditions for the derivatization and resolution by GLC of all stereoisomers of threonine and 4-hydroxyproline are reported. Threonine was in two steps converted to N,O-bisisobutoxycarbonyl 2,2,2-trifluoroethyl ester derivatives, the second of which was performed under anhydrous conditions. As such the enantiomers could pairwise be separated by capillary gas chromatography on a Chirasil-Val column. Since L- and D-threonine eluted much earlier than the corresponding allo forms, quantitative determination of the allothreonine content in D- or L-threonine down to the one percent level could be simply accomplished but also enantiomeric impurities could be determined. Unlike for threonine, the corresponding 4-hydroxyproline isomers could not all be resolved as N,O-bisisobutoxycarbonyl 2,2,2-trifluoroethyl esters on this column. Although diastereomers could still be separated, the allo pair cochromatographed and the resolution for the L- and D-isomers was low. Complete separation of the 4-hydroxyproline isomers could be accomplished as N,O-bisprotected isobutyl amides, the formation of which required three derivatization steps. These were used for the determination of allohydroxyproline.

Chromatography, Gas↗

PubMed1987

Practolol inhibits human skin fibroblast cell mat hydroxyproline accumulation.

Despite being poorly absorbed practolol (N-4-2-hydroxy-3-(1-methyl-ethyl)-amino propoxy phenyl acetamine) inhibited the accumulation of cell mat hydroxyproline, a measure of collagen synthesis, by human skin fibroblasts (DT2PH) in vitro, (ID50 0.8 X 10(-3) M). The degree of inhibition was dependent on the concentration of practolol used and the incubation time. Neither preinitiation of collagen synthesis nor omitting ascorbic acid from the incubation medium modified this inhibitory action. In contrast, in vitro generated metabolites of practol, using normal and aroclor induced hamster liver preparation, and structural analogues of practolol had no effect on cell mat hydroxyproline levels. Related compounds, propranolol, (1-(isopropylamino)-3(1-naphthyl-oxy)2-propranolol), and paracetamol, (N-(4-hydroxyphenyl)acetamide), both inhibited hydroxyproline levels. Fibroblasts derived from uninvolved skin of a psoriasis patient (PS1) were several fold more sensitive to practolol and propranolol than cells derived from normal skin but showed little change in sensitivity towards paracetamol.

Cells, Cultured↗

PubMed1976

Is there a recycling of hydroxyproline?

Rats can produce glycine from hydroxyproline and vice versa. After the injection, hydroxyproline is rapidly converted into glycine and then incorporated into collagen. Later the labelled amino acids in collagen are hydroxyproline, proline, serine, threonine, alanine, and glutamic acid. We suppose that all these labelled amino acids come from glycine.

Amino Acids↗

PubMed1982

Effects of chronic renal failure on wound healing in rats. II. Microscopic study and hydroxyproline assay.

Incisional wounds of the abdominal skin, aponeurosis, stomach and colon were investigated microscopically for a comparison of the findings between uremic and normal rats. The grade of edema and number of inflammatory cells were increased in the rats with uremia and the granulation zone was also larger in the uremics. Hydroxyproline was assayed in the wound tissues by a modification of the technique of Stegemann and Stalder. The hydroxyproline level was lower in the uremics (p less than 0.05) only in the aponeurosis of the 5th postoperative day and in the colon of the 3.5th to 7th day. The correlation coefficient calculated for the blood urea level, biomechanical strength and hydroxyproline level was nil. If these results can validly be extrapolated to patients with chronic renal failure, careful management and avoidance of possible wound infections is of the greatest importance for surgical patients.

Animals↗

PubMed1985

An enzymatic estimation of free hydroxyproline in tissue hydrolysates.

An enzymatic method using 4-hydroxyproline 2-epimerase (EC 5.1.1.9), D-amino acid oxidase (EC 1.4.3.3.), and a colorimetric reagent of the mixture of Ti(IV) and 4-(2-pyridylazo)-resorcinol was found to be useful in the spectrophotometric assay for hydroxyproline in collagenous tissue hydrolysates. It was possible to determine free hydroxyproline in 250 microliter of tissue hydrolysates at concentrations ranging from 1 to 12.5 micrograms. The coefficient of variation was less than 3%, and the correlation between the proposed method and the colorimetric method (K.I. Kivirikko, O. Laitinen, and D. J. Prockop (1967) Anal. Biochem. 19, 249-255) was 0.973. Thus, this method is convenient because it requires less time than the above colorimetric method, and is also reproducible and sensitive.

Amino Acid Isomerases↗

PubMed1979

Automated analysis of hydroxyproline with elimination of non-specific reacting substances.

A modified urinary hydroxyproline method is presented which utilizes an automated technique, Technicon instrumentation and Ehrlich's reagent. Acid hydrolysates are neutralized automatically. Non-specific reacting substances are determined simultaneously with each sample and subtracted as a blank. This method has been found to be superior to the use of charcoal-resin as an absorbent. After blank correction, the mean hydroxyproline excretion of normal and osteoporotic patients are similar. In all groups studied, including Paget's disease, the blanks reresent a significant fraction of total reacting substances and show wide variation between samples. Multiple samples from patients over a two year period show little variation in hydroxyproline excretion when corrected for non-specific reacting substances.

Autoanalysis↗

PubMed1979

A method for the evaluation of 3-hydroxyproline in the urine.

After hydrolysis of the urine by 6 M HCl, 3-hydroxyproline is purified from many interfering substances by 2 steps of chromatography on Dowex 1 X8 resin equilibrated first in the acetate form and secondly in the OH- form. The amino acid is finally evaluated by chromatography on Dowex 50 M82 resin in a Beckman multichrom amino acid analyzer. In 23 normal adult subjects the mean level was 12.5 +/- 3.5 mumol/24 h. In 8 normal children the level was 6.0 +/- 5 mumol/24 h and in 8 teenagers 15.2 +/- 2.85 mumol/24 h. The ratio of 3-hydroxyproline to 4-hydroxyproline seems indicative of a semiological value of this evaluation in cases of basement membrane collagen deterioration.

Adolescent↗