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At least 19 recordsLinked to original sources
PubMed1975

Urinary excretion of free hydroxylysine, peptide-bound hydroxylysine and hydroxylysyl glycosides in physiological conditions.

The amount of urinary hydroxylysine is an index of collagen metabolism. Of the total hydroxylysine measured in normal urine 80 percent is associated with sugars in two glycosidic compounds, glucosyl-galactosyl-hydroxylysine and galactosyl-hydroxylysine, ten percent is free and unglycosylated and the remainder is bound to urinary peptides. The excretion of hydroxylysyl glycosides follow the same physiological variations as urinary hydroxyproline, but it is not influenced by a collagen-free diet. The urinary excretion of hydroxylysyl glycosides, free hydroxylysine and peptide-bound hydroxylysine increases from 6 months of age to puberty. When corrected for urinary creatinine excretion, the largest amounts are found before one year of age. The glucosyl-galactosyl-hydroxylysine/galactosyl-hydroxylysine ratio is lower in the urine of children. After correction of the values to either the body surface area or to the creatinine excretion, no significant differences can be found between the sexes. The different forms of hydroxylysine are discussed.

Adolescent↗
PubMed1978

A method for measuring hydroxylysine and glycosylated hydroxylysines in urine and protein hydrolysates.

A method for measuring hydroxylysine and glycosylated hydroxylysines is described, based on the separation of the 3 compounds by ion-exchange chromatography, followed by spectrophotometric analysis of the hydroxylysine present as glucosylgalactosylhydroxylysine, galactosylhydroxylysine and free hydroxylysine. The method does not require prior preparation of the urine sample nor the use of high-resolution ion-exchange systems. The method is applicable to the determination of the glycosylated hydroxylysine and hydroxylysine content of urine or alkaline hydrolysates of proteins.

Chromatography, Ion Exchange↗
PubMed1979

Urinary excretion of hydroxyproline, hydroxylysine and hydroxylysine glycosides by patients with Paget's disease of bone and carcinoma with metastases in bone.

Patient's with carcinoma metastases in bone and Pagent's disease of bone have different patterns of collagen metabolite excretion. Both forms of bone disease resulted in an increased excretion of total hydroxyproline and the ratio of glucosylgalactosylhydroxylsine to galactosylhydroxylysine was below normal. The excretion of glucosylgalactosylhydroxylysine and galactosylhydroxylysine was increased in all patients with carcinoma metastases in bone while the excretion of glucosylgalactosylhydroxylysine in patients with Paget's disease. The ratio of total hydroxylysine (free hydroxylysine + glycosylated hydroxylysines) to total hydroxyproline was normal in patients with carcinoma metastases in bone and below normal in patients with Paget's disease bosne. The pattern of urinary collagen metabolite excretion is a more specific indicator of the presence of bone disease than is the measurement of the excretion rate of any individual collagen metabolite. Bone diseases of different etiologies may result in different patterns of urinary collagen metabolite excretion.

Bone Neoplasms↗
PubMed1977

Estimation of hydroxylysine in urine and serum of patients with chronic uremia.

Free hydroxylysine and hydroxylysing glycosides were separated from urine and serum extracts on cation exchange resin and assayed spectrophotometrically. The method in conjunction with gel filtration in Bio-Gel P2 allowed to separate from urine also polypeptide hydroxylysine and hydroxylysine bound in small molecules of neutral or acidic character. Glycosylgalactosylhydroxylysineand galactosylhydroxylysine were separated by partition and/or ion exchange chromatography. Patients with chronic renal insufficiency had elevated serum levels and urinary excretion of hydroxylysine glycosides with increased excretion of hydroxylysine bound in polypeptides and in small molecules of neutral or acidic character. The excretion of free hydroxylysine was often within normal limits. When compared to values found in normal growing subjects and in adult patients with increased bone turnover and normal renin function the urinary excretion of hydroxylysine glycosides in chronic uremia was more markedly increased than excretion of hydroxyproline polypeptides and total hydroxyproline.

Bone Diseases↗
PubMed1979

Hydroxylysine-linked glycosides of human complement subcomponent C1q and various collagens.

1. Human C1q, a subcomponent of the first component of complement, contains 67 disaccharides (glucosylgalactose) and 2.4 monosaccharides (galactose) linked to hydroxylysine in one molecule. It was found that 82.6% of the hydroxylsine residues were glycosylated. The suggestion of the possible existence of glucosylgalactosylhydroxylysine reported previously [Yonemasu, Stroud, Niedermeir & Butler (1971) Biochem. Biophys. Res. Commun. 43, 1388--1394] was confirmed. 2. The hydroxylysine-glycosides are not detected in the C-terminal, non-collagen-like, globular regions, but only in the collagen-like regions in the subcomponent C1q molecule. 3. Alpha 1(I) and alpha 2 in pig skin, alpha 1(II) in bovine cartilage and alpha 1(III) in bovine skin collagens contain 2.0, 2.2, 13.2 and 2.0 residues of hydroxylysine-glycosides per molecule, respectively. The percentage of hydroxylysine residues glycosylated in each of these chains is relatively low (on average 38%). 4. Neither the high percentage of hydroxylysine residues glycosylated nor the high values for the ratios of disaccharides to monosaccharides in the subcomponent C1q resembles that in alpha 1(I), alpha 2, alpha 1(II) and alpha 1(III). 5. Similarities between the extent of glycosylation of hydroxylysine residues in collagen-like regions in the subcomponent C1q molecule and that of the collagenous constituents of human glomerular basement membranes, aortic intima, skin A- and B-chains and of bovine anterior lens capsule are discussed.

Animals↗
PubMed1976

Peptide-bound hydroxylysine and large polypeptides related to collagen synthesis.

About 10% of the urinary hydroxylysine is linked to peptides. There is no significant difference between the excretion of peptide-bound hydroxylysine and hydroxylysine measured in the non-dialysable fraction of the urine. Non-dialysable hydroxylysine is highly glycosylated and contains mainly glucosyl-galactosyl-hydroxylysine. It is concluded that the urinary peptide-bound hydroxylysine is present in the non-dialysable collagen polypeptides. Their unusual carbohydrate composition is discussed.

Collagen↗
PubMed1979

Collagen synthesis by cultured skin fibroblasts from siblings with hydroxylysine-deficient collagen.

It has been previously shown that dermis from subjects with hydroxylysine-deficient collagen contains approximately 5% of normal levels of hydroxylysine and sonicates of skin fibroblasts contain less than 15% of normal levels of collagen lysyl hydroxylase activity. However, cultures of dermal fibroblasts from two siblings with hydroxylysine-deficient collagen (Ehlers-Danlos Syndrome Type VI) compared to fibroblasts from normal subjects synthesize collagen containing approximately 50% of normal amounts of hydroxylysine. The lysyl hydroxylase deficient cultures synthesize both Type I and Type III collagen in the same proportion as control cultures. Both alpha 1(I) and alpha 2 chains are similarly reduced in hydroxylysine content. Collagen prolyl hydroxylation by normal collagen lysyl hydroxylation is the same with or without ascorbate supplementation. In mutant cells the rate of prolyl hydroxylation measured after release of inhibition by alpha, alpha'-dipyridyl is the same as in control cells. The rate of lysyl hydroxylation is reduced in mutant cells but only to approximately 50% of normal.

Ascorbic Acid↗
PubMed1977

Determination of hydroxylysine in urine.

A new method for colorimetric determination of urinary hydroxylysine is described. Approximately one-hundredth of human urine collected for 24 hr was diluted to 25 ml and titrated to pH 2.0 with 2 hcl, and then subjected to column chromatography on Dowex 50 X 4 (H+ form). Amino acids were eluted from the column with 1.5 N NH4OH. Hydroxylysine in the elute with 1.5 N NH4OH was separated from the other amino acids, especially from serine and threonine, by preparative paper chromatography. The paper corresponding to hydroxylysine was cut and eluted with water. An aliquot of the eluate with water was oxidized by sodium metaperiodate, and formaldehyde liberated from hydroxylysine was assayed by chromotropic acid reagents, after removing periodate and iodate with Dowex 1 X 8 (formate form). Excretion rate of hydroxylysine in urine of adults was shown to be approximately 110 mumoles per day.

Chromatography↗
PubMed1977

Further studies on the effect of the collagen triple-helix formation on the hydroxylation of lysine and the glycosylations of hydroxylysine in chick-embryo tendon and cartilage cells.

The hydroxylation of lysine and glycosylations of hydroxylysine were studied in isolated chick-embryo tendon and cartilage cells under conditions in which collagen triple-helix formation was either inhibited or accelerated. The former situation was obtained by incubating the tendon cells with 0.6mm-dithiothreitol, thus decreasing their proline hydroxylase activity by about 99%. After labelling with [(14)C]proline, the formation of hydroxy[(14)C]proline was found to have declined by about 95%. Since the hydroxylation of a relatively large number of proline residues is required for triple-helix formation at 37 degrees C, the pro-alpha-chains synthesized under these conditions apparently cannot form triple-helical molecules. Labelling experiments with [(14)C]lysine indicated that the degree of hydroxylation of the lysine residues in the collagen synthesized was slightly increased and the degree of the glycosylations of the hydroxylysine residues more than doubled, the largest increase being in the content of glucosylgalactosylhydroxylysine. Recovery of chick-embryo cartilage cells from temporary anoxia was used to obtain accelerated triple-helix formation. A marked decrease was found in the extent of hydroxylation of the lysine residues in the collagen synthesized under these conditions, and an even larger decrease occurred in the glycosylations of the hydroxylysine residues. The results support the previous suggestion that the triple-helix formation of the pro-alpha-chains prevents further hydroxylation of lysine residues and glycosylations of hydroxylysine residues during collagen biosynthesis.

Animals↗
PubMed1976

Comparative study of carbohydrate-protein complexes. II. Determination of hydroxylysine and its glycosides in human skin and scar collagens by an improved method.

A modification of the existing methods for measuring hydroxylysine, galactosylhydroxylysine, and glucosylgalactosylhydroxylysine is described. The method is based on analysis with an automated amino acid analyzer using a conventional separation system for basic amino acids. The prior removal of acidic and neutral amino acids was necessary. This was achieved by passing an alkaline hydrolysate of collagen through a column of Amberlite CG-120, Type II (H+) and washing the column with 8% aqueous pyridine. A basic fraction containing the hydroxylysine compounds was then recovered from the column by elution with 3 M NH4OH. Model experiments showed that hydroxylysine and its glycosides could be analyzed with an hour and that recoveries exceeded 90%. This method was applied to human tissues to investigate whether the dermal scar is different in collagen composition from normal skin. With the limited number of samples analyzed, the data suggested that long-standing scar tissues reverted to a composition similar to that of normal skin. The composition of hydroxylysine-linked carbohydrate units is also discussed on the basis of the age-related change.

Adolescent↗
PubMed1977

Urinary excretion of hydroxylysine and its glycosides as an index of collagen degradation.

Urimary excretion of hydroxyprolin (Hyp) is one index of total collagen degradation, from all sources. Since some of the Hyp released from collagen may be further metabolized before it is excreted, other markers are necessary to measure collagen breakdown. Excretion of the glycosides of hydroxylysine (Hyl), glucosyl galactosyl hydroxylysine (Hy1[Gl)cGa1]), and galactosyl hydroxylysine (Hyl[Ga)]), more accurately reflects collagen metabolism since these products occur in specificratios in different tissue collagens and are themselves metabolized only to a minor degree. The ratios of total Hy1/Hyp and Hyl(GlcGal)/Hyl(Ga1) were measured in the urine of norma. subjects and of patients with Paget's disease of bone, hyperphosphatasia, and extensive thermal burns. In patients with extensive thermal burns the pattern of urinary Hy1 and its glycosides was consistent with degradation of collagen in dermis and fascia. When bone collagen degradation was dominant, the pattern of urinary metabolites reflected that source. Pagetic bone collagen has an amino acid composition similar to normal bone and Hy1(G1cGa1/Hyl(G1) of 0.396-0.743,vs. normal of 0.474+/-0.088. In untreated patients with severe Paget's disease of bone or hyperphosphatasia (urinary Hyp greater than 2.0 micronmol/mg creatinine) urinary Hyl/Hyp averaged 0.052+/-0.042 (0.042+/-0.009 in normal bone) and Hy1(G1cGa1)/Hy1(Ga1) 0.601+/-0.017 (0.47+/-0.009 in normal bone). When bone resorption was decreased sufficiently with calcitonin or disodium etidronate in these patients, both the urinary ratios of Hy1/Hyp and Hy1(G1cGa1)/Hyl(Gal) rose. In normal subjects treated with calcitonin and excreting relatively little Hyp, the ratio of Hy1/H)P approached 0.7 and Hy1(G1ycGa1)/Hy1(Ga1) approached 3.5. There increased ratios reveal the existence of a source of collagen breakdown other than skin or bone. The first subcompoent of complement, Clq, which has collagen-like sequences, relatively high amounts of Hy1, and most of the glycosylated Hy1 as Hy1(G1cGa1), could be the source of these metabolites.

Adolescent↗
PubMed1979

Chromatographic analysis of hydroxylysine glycosides and acid hydrolyzates.

A single-column chromatographic technique for the analysis of hydroxylysine glycosides and acid hydrolyzates is described. This technique employs a Durrum D-500 amino acid analyzer equipped with a standard 48 cm X 1.8 mm column packed with DC-4A resin. Resolution was achieved with four sodium citrate buffers and four column temperatures. Products of glycoprotein hydrolysis including cysteic acid, methionine sulfoxide, 4-hydroxyproline, alpha-aminobutyric acid, glucosamine, galactosamine, hydroxylysine, tryptophan and the internal standard, norleucine, are resolved. The completely automated procedure takes 185 min per run and can measure amino acid residues in the nanomole range.

Animals↗
PubMed1976

Abnormal properties of collagen lysyl hydroxylase from skin fibroblasts of siblings with hydroxylysine-deficient collagen.

Skin fibroblasts from two siblings with hydroxylysine-deficient collagen collagen (Ehlers-Danlos syndrome, type VI) contained normal levels of collagen prolyl hydroxylase activity but were markedly deficient in collagen lysyl hydroxylase activity. The deficiency was evident in all fractions of cell lysates, in low and high ionic strength buffers, and in detergent. Assays of mixtures of wild-type and mutant cell lysates indicated no activation of mutant enzyme by factors in wild-type cells or inhibition of normal enzyme by material in mutant cells. Wild type or mutant cells cultured with ascorbic acid (50 mug/ml of culture medium, added daily) contained approximately the same level of lysyl hydroxylase activity as cells cultured without ascorbate, but prolyl hydroxylase activity without ascorbate was depressed in both an average of 41%. The mutant lysyl hydroxylase was less stable at 37 degrees C than the wild type and did not form high molecular weight aggregates in low ionic strength buffers, as did the control enzyme. The activity of the mutant enzyme was maximally stimulated after dialysis against buffer solutions containing 10 mM dithiothreitol. When assayed in 100 muM dithiothreitol, the mutant enzyme exhibited a higher apparent Km for ascorbate (20 muM) than the wild type (4 muM). In 1.0 mM dithiothreitol the mutant enzyme's apparent Km for ascorbate was reduced to 5 muM. Wild type and mutant enzymes had the same apparent Km for alpha-keto-glutarate (20 muM). The properties of prolyl hydroxylase in wild type and mutant cells were identical: apparent Km's for ascorbate and alpha-ketoglutarate were 100 muM and 20 muM, respectively. If mutant enzyme protein with altered kinetic properties is the only enzyme functioning to hydroxylate lysyl residues in collagen, the variations in hydroxylysine content observed in collagen from different tissues in the subjects reported here could be in part due to differences in cofactor concentrations and in rate and sequence of events in collagen synthesis in different tissues.

Ascorbic Acid↗
PubMed1977

Guanosine triphosphate: 5-hydroxylysine phosphotransferase in rat kidney cortex.

An enzyme which catalyzes the transfer of the gamma-phosphate from GTP onto 5-hydroxylysine was partially purified from rat kidney cortex by means of acid precipitation and DEAE-Sephadex A-50 column chromatography. The enzyme activity was assayed by measuring the transfer of [32P] from gamma-[32P]-GTP to materials not adsorbed by charcoal. This partially purified enzyme showed essentially no GTP phosphohydrolase activity and an optimal pH of 8.0. An apparent Km of about 23.8 mumol/1 was obtained with respect to 5-hydroxylysine. Mg2+ was required for the activity of this enzyme. Ethanolamine, L-lysine, L-ornithine and choline inhibited the enzyme but L-threonine, L-serine and hydroxy-L-proline did not. None of these compounds severed as substrate for this enzyme.

Animals↗
PubMed1979

Studies on the formation of N6-hydroxylysine in cell-free extracts of Aerobacter aerogenes 62-1.

We have investigated conditions optimal for the conversion of L-lysine to its N6-hydroxy derivative by partially purified cell-free extracts of Aerobacter aerogenes 62-1. The enzyme system was highly specific to L-lysine: the D-isomer and, the N2- or N6-derivatives of lysine, and alpha-amino acids were not hydroxylated. Most of the latter compounds had little effect onthe hydroxylation of L-lysine. However, -l-glutamic acid and L-glutamine enhanced the hydroxylation, with half-maximal activation achieved at 100 micrometers concentration of the effector. The Km values for pyruvate and L-(+)-lactate (compounds known to stimulate N-hydroxylysine formation) were found to be approx. 100 micrometers. The data show that N-hydroxylation of the amino acid precedes acylation in the biosynthesis of hydroxamic acid in A. aerogenes 62-1.

Antimetabolites↗
PubMedDate not supplied

Hydroxyproline and hydroxylysine in different tissues of human embryos.

The collagen content in various tissues of human embryos was studied at four different steps of the maturation process. The umbilical cord of a 16-17 week old embryo was found to be active in collagen biosynthesis, Tibia, articular cartilage and skin showed of a peak of total hydroxyproline in the 16-17th week, decreasing later on, while the hydroxyproline decreased in umbilical cord from the 15-16th week to the 24th week. Hydroxylysine followed the hydroxyproline changes in articular cartilage and umbilical cord.

Bone and Bones↗
PubMed1975

Age-related variations in glycosylation of hydroxylysine in human and rat skin collagens.

The extent of glycosylation of hydroxylysine in human skin collagen rapidly decreased during maturation and then gradually increased in proportion to the age. This decrease of glycosylation observed during maturation was also confirmed in whole, soluble and insoluble collagens from rat skin. These findings may contribute to the investigations on the functional role of glycosylation and also on the mechanism of maturational as well as senile processes.

Adolescent↗