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PubMed1999

Substituted 4-hydroxyproline di- and tri-peptides as cytotoxic agents.

4-Hydroxyproline di- and tri-peptides and N-cbz-hydroxypropyl- glycinamides were observed to be potent cytotoxic agents against the growth of suspended single cells, L-1210, Tmolt3, and HeLa-S3. The agents were not as potent against the growth of cultured solid tumor cells. Selected derivatives were investigated for their mode of action in Tmolt3 leukemia cells. The compounds selectively inhibited DNA synthesis at 50 and 100 microM. The target site of action of the agents appeared to be the purine de novo pathway with marked inhibition of the activities of the two regulatory enzymes of the pathway, i.e. PRPP amido-transferase and IMP dehydrogenase. d[NTP] pools were reduced by the agents consistent with their overall reduction of DNA synthesis. Other marginally inhibited targets of the agents were r-RNA polymerase and TMP-kinase activities. The DNA molecule itself did not appear to be a target of these agents.

Animals↗
PubMed1978

[The judgement of collagen metabolism by hydroxyproline in plasma and urine and plasma collagenic peptidase under different diet (author's transl)].

In 34 subjects--coal workers with pneumoconiosis, patients with collagenic diseases and healthy subjects--the daily urinary excretion of hydroxyproline (HP) and the plasma concentrations of HP and of collagenic peptidase have been measured during one week under HP-free and HP-enriched diet. It is shown that a 24-hour period of HP-free diet is necessary and sufficient before collecting urine or plasma for diet independent measurements of total or non-protein bound HP. Concentrations in plasma correlate well with the amounts excreted in urine. Collagenic peptidase is independent from the diet and well suited for assessment of the activity of the metabolism of collagene. There are no differences between healthy subjects and coal workers with pneumoconiosis.

Adult↗
PubMed1976

Self complementarity in messenger RNA of collagen. I. Possible hairpin structures in regions coding for oligopeptides of glycine, proline (hydroxyproline) and alanine.

The periodic protein collagen is of special interest for the study of the relationship which exists between the structure of a protein and that of its mRNA, because oligopeptides containing glycine, proline (hydroxyproline) and alanine occur with great frequency in it. Collagen is particularly rich in these amino acids, which have codons containing only G and/or C in the obligatory first and second positions. If unlimited choice of codons for all amino acids were to occur, the stretch of mRNA coding for an alpha-chain should contain about 40% G and 31% C (Bachra et al., 1974). These high values suggest that a considerable degree of secondary structure will occur, unless selective codon use would result in the avoidance of G and C in optional third codon positions. In the present paper putative secondary structure formation in collagen mRNA was studied. This was done by studying the positions and frequencies of hairpin structures which could contain stem sections composed of the coding triplets of the above mentioned amino acids and hairpin sections of 4-40 bases. Calculation of the free energy contributions of such hairpin structures, using published values for the contributions of base-pair stacking, hairpin, bulge and interior loops and also taking into account the possible minimum number of base-pairs required for helix nucleation from a single-strand RNA (3 adjacent AU-pairs or 1 or 2 adjacent GC-pairs) led to the following conclusions. A considerable number of alternative, mutually exclusive hairpins can be constructed.

Alanine↗
PubMed1983

Urinary hydroxyproline levels in patients with prostatic carcinoma.

In this study daily urinary hydroxyproline (HOP) levels were evaluated in 26 patients with advanced prostatic cancer and 15 patients with BPH. In patients with prostatic cancer--the ones with bone metastases proved by bone scanning--urinary HOP levels were found to be 69.58 mg/l/day and in those without metastases the levels amounted to 22.55 mg/l/day. In patients with BPH, serving as controls, urinary HOP was 12.80 mg/l/day. Urinary HOP Levels in cancer patients were statistically higher than in the control group. This difference was even more significant in patients with bone metastases. The method detects small metastatic foci of low activity, therefore it may be used also in smaller centres and for effective monitoring of therapy.

Aged↗
PubMed1975

Hydroxyproline-2-epimerase of Pseudomonas: active-site peptides.

Hydroxyproline-2-epimerase was treated with 14C-iodoacetate under conditions that produced almost complete inactivation of the enzyme and concomitant incorporation of almost one molar equivalent of iodoacetate. Both processes were prevented by saturating concentrations of substrate. From reaction mixtures in which both incorporation and inactivation were 85 to 90% complete, two radioactive tryptic peptides were isolated by paper chromatography-electrophoresis. The incorporated radioactivity was divided between the peptides in an approximately 2:1 ratio. Analysis of the isolated peptides suggested that they both contained 9 amino acids and had similar composition; one appeared to be a lysine, the second an arginine peptide. Attempts to sequence each peptide failed, apparently because of the conversion of the S-carboxymethylcysteine to S-carboxymethylcysteine sulfone, indicating that the cysteine residue was N-terminal in each peptide.

Amino Acid Isomerases↗
PubMed1984

Bone mass as referent for urinary hydroxyproline excretion: age and sex-related changes in 125 normals and in primary hyperparathyroidism.

Fasting urinary hydroxyproline: creatinine ratio (OHPr:Cr) and bone mineral content of the forearm (BMC) were measured in 125 normals, 67 females and 58 males, aged 20-79 years, and in 15 patients with primary hyperparathyroidism. In normals, both variables were significantly correlated to age and sex. The interrelation of OHPr:Cr and BMC was studied in subgroups of normals who were supposedly in metabolic balance, that is, females aged 20-39 years (n = 24) and males aged 20-49 years (n = 29). In both sexes OHPr:Cr and BMC were positively correlated: r = 0.60 and 0.58, respectively (P less than 0.001). On this basis, BMC correction of all OHPr:Cr values was undertaken now revealing a stable increased level of bone resorption per unit of bone mass in postmenopausal females. In males OHPr:Cr per unit of BMC remained unaltered throughout life. In primary hyperparathyroidism, in which increased bone resorption is inherent, the discriminatory power of OHPr:Cr was significantly improved when calculated per unit of BMC (P less than 0.001). These observations suggest that estimation of bone resorption by use of OHPr:Cr requires adjustment for differences in bone mass.

Adult↗
PubMed1981

Effect of vitamin D deficiency on urinary excretion of connective tissue derivatives (hydroxyproline and glycosaminoglycans) in rats.

The urinary excretion of two connective tissue metabolites was studied in both control and vitamin D deficient rats. Hydroxyproline (HyPRO) excretion was determined after 2, 13 and 22 months (experiment I). It decreased with aging in animals receiving the control diet. On the contrary, this excretion increased as a function of age in vitamin D deficient animals. At the age of 22 months, HyPRO excretion was respectively 31 and 1708 micrograms a day in control and deficient animals. HyPRO and glycosaminoglycans (GAG) excretion was measured on a group of both control and vitamin D deficient rats at the age of 21 months (experiment II). These results confirm the high excretion of HyPRO in deficient animals. On the contrary, the GAG excretion was higher in control animals than in deficient ones, the mean excretion being respectively 412 and 234 micrograms a day.

Animals↗
PubMedDate not supplied

Effects of age on the urinary excretion of total and non-dialyzable hydroxyproline.

This study was carried out in order to investigate the effects of age on the urinary excretion of total and non-dialyzable hydroxyproline (OHPr) in normal subjects. We found that total urinary OHPr was negatively correlated with age but, by means of partial regression analysis, no correlation was found after correction for changes in creatinine clearance; on the contrary, non-dialyzable OHPr showed a statistically significant negative correlation with age (r = -0.56) even when creatinine clearance was held constant (p less than 0.05). A highly significant direct correlation was found between total and non-dialyzable OHPr in the whole group (r = 0.54) and when only premenopausal women and men under 60 years of age were considered (r = 0.51). No correlation was found when postmenopausal women and men more than 60-year-old were taken into account. Our data appear to indicate that also the decrease in osteogenetic activity is responsible for the physiological late involutional bone loss; they also show the importance of hormonal changes in inducing an uncoupling between bone formation and resorption.

Adult↗
PubMed1984

Acute effects of removal of parathyroid adenoma on plasma and urinary hydroxyproline levels.

This study was carried out to investigate early effects of parathyroidectomy (PTx) on bone matrix collagen metabolism. Eleven patients suffering from primary hyperparathyroidism were studied by measuring urinary excretion of hydroxyproline (OHPr) and cAMP in samples collected before PTx and, on the day of surgery, at intervals of 1-3 h for the first 10 h and then at longer intervals. In six patients nondialyzable urinary OHPr and free plasma aminoacid levels were also assayed. We found that the average period required for OHPr/Cr ratio and plasma OHPr to reach normal values was longer than the mean time required for cAMP/Cr ratio to reach normal limits. In all patients the total amount of nondialyzable OHPr decreased in the first 24 h after PTx but thereafter a daily increase in the urinary excretion of nondialyzable component was seen, so that the fractional amount of nondialyzable OHPr in the fourth postoperative day (26.8 +/- 5.2 SE) was significantly higher than that of preoperative one (6.1 +/- 1.0; p less than 0.02). Our results confirm that PTx induces a reduction in the rate of bone collagen resorption and indicate that changes of OHPr/Cr ratio and free plasma OHPr values may be considered useful indices of successful parathyroid surgery, even though they lag behind those of cAMP. The different behavior of total and nondialyzable OHPr after surgery indicates that acute deficiency of parathyroid hormone induces a positive uncoupling of the two processes of bone remodeling, thus supporting the view that the acute direct effect of the hormone on bone formation is an inhibition of this process.

Adenoma↗
PubMed1999

Hydroxyproline interference during the gas chromatographic analysis of D/L aspartic acid in human dentine.

The proportion of D- to L-enantiomers of aspartic acid in metabolically isolated proteins has been used by forensic scientists to estimate age at death. We have demonstrated the interference of a derivative of hydroxyproline (N-TFA isopropyl Hyp ester) with the N-TFA isopropyl L-Aspartic (Asp) acid ester during gas chromatography of amino acids. This has serious implications for the accurate quantification of the D- to L-Asp ratio extracted from collagenous proteins. Having demonstrated the potential for this co-elution in amino acid standards, acid-soluble dentine proteins and non-mineralised collagen, we argue that this problem can be overcome either by high resolution separation or by analysis of the (Hyp-poor) non-collagenous protein fraction.

Aspartic Acid↗
PubMed2002

Sustained release of cis-hydroxyproline in the treatment of experimental proliferative vitreoretinopathy in rabbits.

PURPOSE: To evaluate the efficacy of sustained-release cis-4-hydroxyproline (CHP), a proline analog that inhibits collagen secretion, on experimental proliferative vitreoretinopathy (PVR) in rabbits. METHODS: To demonstrate the sustained release of CHP we developed scleral implants weighing 8.5 mg made of a homogeneous mixture of poly( D, L-lactide-co-glycolide) (PLGA) and various doses of CHP. The CHP release profiles were evaluated by high-performance liquid chromatography in vitro. Scleral implants loaded with 20% and 15% of CHP and made from PLGA (copolymer ratios 65/35 and 50/50; mean molecular weights 103,000 and 93,000, respectively) were used to treat experimental PVR and the efficacy was studied. In treated eyes, two PLGA 65/35 implants ( n=7), PLGA 50/50 implants ( n=6), or a PLGA 65/35 and a PLGA 50/50 implant ( n=9) were inserted at the pars plana, followed by PVR induction with autologous fibroblasts. Control eyes ( n=18) received two implants without CHP. Ocular tissue toxicity was evaluated histologically. RESULTS: In vitro release studies demonstrated a triphasic release pattern. The PLGA 65/35 and PLGA 50/50 implants released CHP over 4 and 7 weeks, respectively. The PLGA 65/35 implants decreased the incidence of retinal detachment from 89% (in controls) to 57% on day 28. When both PLGA 65/35 and PLGA 50/50 implants were used, the inhibitory effect was synergistically enhanced ( p=0.0034), while implantation with only PLGA 50/50 implants had no significant effect on PVR. No toxic reactions were observed. CONCLUSION: These results suggest that the biodegradable polymeric implants containing CHP represent a potential treatment for PVR.

Absorbable Implants↗
PubMed1999

Molecular characterization of two light-induced, gamete-specific genes from Chlamydomonas reinhardtii that encode hydroxyproline-rich proteins.

Gametic differentiation in Chlamydomonas reinhardtii is a two-step process, which is controlled by the sequential action of the two extrinsic signals, nitrogen starvation and blue light. The gamete-specific genes GAS28 and GAS29 are expressed in the late phase of gametogenesis. Their light-induced expression is restricted to cells that have completed the first, nitrogen starvation-activated, phase of differentiation. A comparison of the two genes revealed striking similarities as well as differences. Their most prominent shared feature is an extended sequence homology of over 90% in their 5'-untranslated regions, suggesting a role in translational regulation. GAS28 and GAS29 both encode hydroxyproline-rich proteins (HRGPs) of very similar sizes that exhibit typical features of volvocalean cell wall constituents. GAS28 shows a high degree of homology with the Volvox pherophorin gene family, suggesting a relationship between these genes.

Amino Acid Sequence↗
PubMed1990

Determination of 4-hydroxyproline in collagen by gas chromatography/mass spectrometry.

Derivatization of 4-hydroxyproline (Hyp) in collagen using trifluoroacetylation and methanol esterification produces two derivatives when analyzed by gas chromatography/mass spectrometry (GC/MS). The diacyl derivative N,O-bis(trifluoroacetyl)-4-hydroxy-L-proline methyl ester (N,O-TFA-Hyp) formed in this manner has a shorter retention time and different fragmentation pattern by GC/MS as compared to the slower eluting monoacetylated species N-trifluoroacetyl-4-hydroxy-L-proline methyl ester (N-TFA-Hyp). By selected ion monitoring of the appropriate ions of either N,O-TFA-Hyp (m/z 164, 278) or N-TFA-Hyp (m/z 164, 182) efficient quantitation of Hyp in collagen is possible within the broad range of 5-1000 ng with a lower limit of detection of 0.5 ng per injection. Measurement of 18O2 incorporation into collagen is possible by selected ion monitoring of the m/z 182 ion formed only from the monoacetylated derivative, N-TFA-Hyp, produced by methanol solvolysis of the N,O-TFA-Hyp derivative, as proposed herein.

Acetic Anhydrides↗
PubMed1976

Inhibition of hydroxyproline synthesis by palladium ions.

Palladium ions, administered as PdSO4, markedly affect the incorporation of L-[3,4-3H2] proline into non-dialyzable fractions in 10-day chick embryo cartilage explants with a 55-65% reduction in the concentration range 0.06-0.6 mM. Under these conditions the synthesis of [3H]hydroxyproline was nearly completely inhibited. Experiments with prolyl hydroxylase (EC 1.14.11.2) indicated a strong irreversible inhibition of the enzyme with a competition between Fe2+ and Pd2+. The Ki for the inhibition was 0.02 mM. Pd2+-treated enzyme remained inactive after extensive dialysis. These studies suggest that Pd2+ may inhibit collagen synthesis by replacing Fe2+ in the active site of prolyl hydroxylase and forming strong complexes with the enzyme. These studies also point to a potential mechanism of Pd2+ toxicity.

Animals↗
PubMed1975

High-molecular-weight hydroxyproline-protein in relation to immunoglobulins M (IgM) in human blood serum.

The content of the high-molecular-weight protein-bound hydroxyproline (Hyp) and IgM level in the sera of 30 healthy persons and 29 patients showing changes in gamma and/or beta globulin levels was determined. Statistically significant correlations between quantities of these components have been found. On the base of the present results as well as the results of previous studies authors suggest that the high-molecular-weight Hyp-protein contains immunoglobulin of the IgM class.

Adult↗
PubMed1978

Fluorimetric determination of free hydroxyproline and proline in blood plasma.

A selective and sensitive assay of hydroxyproline in blood plasma is presented. The technique uses ion exchange chromatography followed by reaction with 7-chloro-4-nitrobenzofurazan (NBD choloride) and continuous recording of the resulting fluorescence (gamma ex=465 nm, gamma fl=535 nm). Proline and prolyl-and hydroxyprolyl-peptides can also be measured by this system. For hydroxy proline, the method is more sensitive than procedures using ninhydrin or p-dimethylaminobenzaldehyde.

Fluorometry↗
PubMed1993

Selective and sensitive determination of urinary total proline and hydroxyproline by gas chromatography with flame photometric detection.

A selective and sensitive method for the determination of total urinary proline (Pro) and hydroxyproline (Hyp) by gas chromatography (GC) was developed. After acid hydrolysis of urine, primary amino compounds were eliminated by reaction with o-phthaldialdehyde. Subsequently, Pro and Hyp were converted into their N-dimethylthiophosphoryl methyl ester derivatives and then determined by GC with flame photometric detection using a DB-5 capillary column. The derivatives were volatile and stable, giving single and symmetrical peaks. The detection limits for Pro and Hyp were 0.1 and 0.2 pmol injected, respectively. 3,4-Dehydroproline was used as an internal standard. The calibration curves for Pro and Hyp in the range 0.4-10 nmol were linear and sufficiently reproducible for quantitative determination. Overall recoveries of Pro and Hyp added to urine samples ranged from 93% to 103%. By using this method, Pro and Hyp in a small urine sample could be accurately and precisely determined without any influence from other constituent substances.

Chromatography, Gas↗