Dipeptidyl peptidase IV, a kidney brush-border serine peptidase

Dipeptidyl peptidase IV, an enzyme that releases dipeptides from substrates with N-terminal sequences of the forms X-Pro-Y or X-Ala-Y, was purified 300-fold from pig kidney cortex. The kidney is the main source of the enzyme, where it is one of the major microvillus-membrane proteins. Several other tissues contained demonstrable activity against the usual assay substrate glycylproline 2-naphthylamide. In the small intestine this activity was greatly enriched in the microvillus fraction. In all tissues examined, the activity was extremely sensitive to inhibition by di-isopropyl phosphorofluoridate (Dip-F), but relatively resistant to inhibition by phenylmethylsulphonyl fluoride. It is a serine proteinase which may be covalently labelled with [32P]Dip-F, and is the only enzyme of this class in the microvillus membrane. The apparent subunit mol.wt. estimated by sodium dodecyl-sulphate/polyacrylamide-gel electrophoresis and by titration with [32P]Dip-F was 130 000. Gel-filtration and sedimentation-equilibrium methods gave values in the region of 280 000, which is consistent with a dimeric structure, a conclusion supported by electron micrographs of the purified enzyme. Among other well-characterized serine proteinases, this enzyme is unique in its membrane location and its large subunit size. Investigation of the mode of attack of the peptidase on oligopeptides revealed that it could hydrolyse certain N-blocked peptides, e.g. Z-Gly-Pro-Leu-Gly-Pro. In this respect it is acting as an endopeptidase and as such may merit reclassification and renaming as microvillus-membrane serine peptidase.

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Bovine lens aldehyde dehydrogenase. Purification and preliminary characterization

Biochemical Journal ◽

10.1042/bj2150351 ◽

1983 ◽

Vol 215 (2) ◽

pp. 351-359 ◽

Cited By ~ 14

Author(s):

H H Ting ◽

M J C Crabbe

Keyword(s):

Aldehyde Dehydrogenase ◽

Polyacrylamide Gel Electrophoresis ◽

Sodium Dodecyl ◽

Gel Filtration ◽

Sedimentation Equilibrium ◽

Bovine Lens ◽

Systemic Corticosteroids ◽

Apparent Homogeneity ◽

Stokes Radius ◽

Equilibrium Ultracentrifugation

Cytoplasmic aldehyde dehydrogenase from bovine lens was purified to apparent homogeneity by using ion-exchange and affinity chromatography. Sedimentation-equilibrium ultracentrifugation, gel-filtration chromatography and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis show that the enzyme is a dimer of Mr 114000, with subunits of Mr 57000. The enzyme does not dissociate into monomers in the presence of Ca2+ or Mg2+. The enzyme has a pI of 5.0, an activation energy of 35.1kJ/mmol and a pK value of 8.6 with acetaldehyde as substrate. The enzyme is a prolate ellipsoid with a Stokes radius of 4nm. Progesterone, deoxycorticosterone and chlorpropamide inhibited enzyme activity, and this inhibition may play a role in cataract formation in patients maintained on systemic corticosteroids and in tablet-dependent diabetics.

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Novel Extracellular x-Prolyl Dipeptidyl-Peptidase (DPP) from Streptococcus gordonii FSS2: an Emerging Subfamily of Viridans Streptococcal x-Prolyl DPPs

Infection and Immunity ◽

10.1128/iai.69.9.5494-5501.2001 ◽

2001 ◽

Vol 69 (9) ◽

pp. 5494-5501 ◽

Cited By ~ 23

Author(s):

J. M. Goldstein ◽

A. Banbula ◽

T. Kordula ◽

J. A. Mayo ◽

J. Travis

Keyword(s):

Heart Valves ◽

Thrombus Formation ◽

Polyacrylamide Gel Electrophoresis ◽

Sodium Dodecyl ◽

Gel Filtration ◽

Critical Factor ◽

Dipeptidyl Peptidase ◽

Streptococcus Gordonii ◽

Pcr Cloning

ABSTRACT Streptococcus gordonii is generally considered a benign inhabitant of the oral microflora, and yet it is a primary etiological agent in the development of subacute bacterial endocarditis (SBE), an inflammatory state that propagates thrombus formation and tissue damage on the surface of heart valves. Strain FSS2 produced several extracellular aminopeptidase and fibrinogen-degrading activities during growth in culture. In this report we describe the purification, characterization, and cloning of a serine class dipeptidyl-aminopeptidase, an x-prolyl dipeptidyl-peptidase (Sg-xPDPP, for S. gordonii x-prolyl dipeptidyl-peptidase), produced in a pH-controlled batch culture. Purification of this enzyme by anion exchange, gel filtration, and hydrophobic interaction chromatography yielded a protein monomer of approximately 85 kDa, as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE) under denaturing conditions. However, under native conditions, the protein appeared to be a homodimer on the basis of gel filtration and PAGE. Kinetic studies indicated that purified enzyme had a unique and stringent x-prolyl specificity that is comparable to both the dipeptidyl-peptidase IV/CD26 and lactococcal x-prolyl dipeptidyl-peptidase families. Nested PCR cloning from an S. gordonii library enabled the isolation and sequence analysis of the full-length gene. A 759-amino-acid polypeptide with a theoretical molecular mass of 87,115 Da and a calculated pI of 5.6 was encoded by this open reading frame. Significant homology was found with the PepX gene family fromLactobacillus and Lactococcus spp. and putative x-prolyl dipeptidyl-peptidases from other streptococcal species. Sg-xPDPP may serve as a critical factor for the sustained bacterial growth in vivo and furthermore may aid in the proteolysis of host tissue that is commonly observed during SBE pathology.

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The purification and molecular properties of the tryptophan-sensitive 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase from Neurospora crassa

Biochemical Journal ◽

10.1042/bj1970427 ◽

1981 ◽

Vol 197 (2) ◽

pp. 427-436 ◽

Cited By ~ 9

Author(s):

G A Nimmo ◽

J R Coggins

Keyword(s):

Molecular Weight ◽

Neurospora Crassa ◽

Gel Electrophoresis ◽

Polyacrylamide Gel Electrophoresis ◽

Sodium Dodecyl ◽

Gel Filtration ◽

Deae Cellulose ◽

Polyacrylamide Gel ◽

Sedimentation Equilibrium ◽

Phosphate Synthase

Neurospora crassa contains three isoenzymes of 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase, which are inhibited by tyrosine, tryptophan and phenylalanine respectively, and it was estimated that the relative proportions of the total activity were 54%, 14% and 32% respectively. The tryptophan-sensitive isoenzyme was purified to homogeneity as judged by polyacrylamide-gel electrophoresis and ultracentrifugation. The tyrosine-sensitive and phenylalanine-sensitive isoenzymes were only partially purified. The three isoenzymes were completely separated from each other, however, and can be distinguished by (NH4)2SO4 fractionation, chromatography on DEAE-cellulose and Ultrogel AcA-34 and polyacrylamide-gel electrophoresis. Polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate indicated that the tryptophan-sensitive isoenzyme contained one type of subunit of molecular weight 52000. The molecular weight of the native enzyme was found to be 200000 by sedimentation-equilibrium centrifugation, indicating that the enzyme is a tetramer, and the results of cross-linking and gel-filtration studies were in agreement with this conclusion.

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The molecular weight and properties of a neutral metallo-endopeptidase from rabbit kidney brush border

Biochemical Journal ◽

10.1042/bj1370489 ◽

1974 ◽

Vol 137 (3) ◽

pp. 489-495 ◽

Cited By ~ 125

Author(s):

M. A. Kerr ◽

A. J. Kenny

Keyword(s):

Molecular Weight ◽

Brush Border ◽

Sodium Dodecyl Sulphate ◽

Guanidine Hydrochloride ◽

Polyacrylamide Gel Electrophoresis ◽

Sodium Dodecyl ◽

Gel Filtration ◽

Atomic Absorption Spectrophotometry ◽

Sedimentation Equilibrium ◽

Rabbit Kidney

1. Some properties of a brush-border neutral endopeptidase purified from rabbit kidney were investigated. The peptidase was assayed by its ability to hydrolyse [125I]iodoinsulin B chain. 2. The enzyme was found to be homogeneous when studied in the analytical ultracentrifuge and stained as a single glycoprotein band after electrophoresis in polyacrylamide gels. 3. The molecular weight was estimated by gel filtration in columns of Sephadex G-200, by polyacrylamide-gel electrophoresis in the presence of 2-mercapto-ethanol and sodium dodecyl sulphate and by sedimentation equilibrium in the ultra-centrifuge. The estimates fell within the range 87000–96000. The mean from two sedimentation equilibrium experiments was 93000, though this estimate may be slightly inflated because of the carbohydrate component of the enzyme. No evidence of dissociation into smaller subunits was obtained in the presence of thiol, sodium dodecyl sulphate or guanidine hydrochloride. 4. The endopeptidase was maximally active at pH6.0, although in phosphate buffer, which was strongly inhibitory, an optimum above pH8 was observed. 5. The enzyme was not affected by di-isopropyl phosphofluoridate nor by several thiol reagents. It was, however, strongly inhibited by many thiols and by EDTA and other chelating agents. 6. Although activity of the EDTA-treated enzyme could be partially restored by various bivalent metal ions, the optimum concentration for its reactivation by Zn2+ was lower than that for other ions. This metal was detected in the enzyme preparation by atomic absorption spectrophotometry in an amount equivalent to approximately one atom/mol. 7. The enzyme is the only endopeptidase shown to be located in the kidney brush border and is the first mammalian example of a neutral Zn2+- activated endopeptidase to be characterized.

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Proteins of the kidney microvillar membrane. The amphipathic form of dipeptidyl peptidase IV

Biochemical Journal ◽

10.1042/bj1790379 ◽

1979 ◽

Vol 179 (2) ◽

pp. 379-395 ◽

Cited By ~ 92

Author(s):

D C Macnair ◽

A J Kenny

Keyword(s):

Amino Acid ◽

Polyacrylamide Gel Electrophoresis ◽

Gel Filtration ◽

Dipeptidyl Peptidase ◽

Dipeptidyl Peptidase Iv ◽

Amino Acid Sequences ◽

Carboxypeptidase Y ◽

Terminal Amino Acid ◽

Hydrophobic Domain ◽

Terminal Amino

Dipeptidyl peptidase IV was solubilized from the microvillar membrane of pig kidney by Triton X-100. The purified enzyme was homogeneous on polyacrylamide-gel electrophoresis and ultracentrifugation, although immunoelectrophoresis indicated that amino-peptidase M was a minor contaminant. A comparison of the detergent-solubilized and proteinase (autolysis)-solubilized forms of the enzyme was undertaken to elucidate the structure and function of the hydrophobic domain that serves to anchor the protein to the membrane. No differences in catalytic properties, nor in sensitivity to inhibition by di-isopropyl phosphorofluoridate were found. On the other hand, several structural differences could be demonstrated. Both forms were about 130,000 subunit mol.wt., but the detergent form appeared to be larger by no more than about 4,000. Electron microscopy showed both forms to be dimers, and gel filtration revealed a difference in the dimeric mol.wt. of about 38 000, mainly attributable to detergent molecules bound to the hydrophobic domain. Papain converted the detergent form into a hydrophilic form that could not be distinguished in properties from the autolysis form. A hydrophobic peptide of about 3500 mol.wt. was identified as a product of papain treatment. The detergent and proteinase forms differed in primary structure. Partial N-terminal amino acid sequences were shown to be different, and the pattern of release of amino acids from the C-terminus by carboxypeptidase Y was essentially similar. The results are consistent with a model in which the protein is anchored to the microvillar membrane by a small hydrophobic domain located within the N-terminal amino acid sequence of the polypeptide chain. The significance of these results in relation to biosynthesis of the enzyme and assembly in the membrane is discussed.

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Purification and characterization of the seven cyanogen bromide fragments of human serum transferrin

Biochemical Journal ◽

10.1042/bj1390163 ◽

1974 ◽

Vol 139 (1) ◽

pp. 163-168 ◽

Cited By ~ 18

Author(s):

Michael R. Sutton ◽

K. Brew

Keyword(s):

Human Serum ◽

Cyanogen Bromide ◽

Polyacrylamide Gel Electrophoresis ◽

Sodium Dodecyl ◽

Gel Filtration ◽

Sedimentation Equilibrium ◽

High Yield ◽

Serum Transferrin ◽

Human Serum Transferrin ◽

Equilibrium Ultracentrifugation

1. Procedures are described for the isolation of seven distinct cyanogen bromide fragments in high yield from human serum transferrin. 2. Cyanogen bromide-cleaved transferrin is separated into three fragments (CN-A, CN-B and CN-C) by gel filtration with Sephadex G-100. 3. Four peptides are obtained from CN-A (the largest fragment) after reduction and carboxamidomethylation, by gel filtration in acidic solvents. Two peptides are similarly obtained from fragment CN-B, whereas fragment CN-C is a single cystine-free peptide. 4. The molecular weights of the seven peptides, as determined by polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate, by sedimentation-equilibrium ultracentrifugation and by sequence studies, range from 3100 to 27000. Together they account for a molecular weight of 76200 for transferrin. 5. The two largest fragments contain the carbohydrate attachment sites of the protein, and the smallest fragment is derived from the N-terminus. 6. The amino acid compositions and N-terminal groups of the fragments are reported and the results compared with those of previous investigations.

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Proteins of the Kidney Microvillar Membrane; Analysis by Sodium Dodecyl Sulphate-Polyacrylamide Gel Electrophoresis and Crossed Immunoelectrophoresis

Clinical Science ◽

10.1042/cs0650551 ◽

1983 ◽

Vol 65 (5) ◽

pp. 551-559 ◽

Cited By ~ 11

Author(s):

Michael T. Abbs ◽

A. John Kenny

Keyword(s):

Alkaline Phosphatase ◽

Sodium Dodecyl Sulphate ◽

Gel Electrophoresis ◽

Polyacrylamide Gel Electrophoresis ◽

Sodium Dodecyl ◽

Human Kidney ◽

Neutral Endopeptidase ◽

Dipeptidyl Peptidase ◽

Dipeptidyl Peptidase Iv ◽

Polyacrylamide Gel

1. A microvillar fraction was prepared from human kidney cortex. This fraction was seven to 10 times enriched in aminopeptidases N and A, γ-glutamyltransferase, dipeptidyl peptidase IV, neutral endopeptidase and alkaline phosphatase. 2. Dipeptidyl peptidase IV activity of human renal microvilli could be inhibited by di-isopropylphosphorofluoridate and neutral endopeptidase activity by phosphoramidon. 3. Nearly all the activity of aminopeptidases A and N could be removed from the membrane by treatment with papain, but only 19% and 33% of dipeptidyl peptidase IV and γ-glutamyltransferase activities were released under the same conditions. Neutral endopeptidase and alkaline phosphatase were not solubilized by papain. Treatment with elastase gave results similar to papain, except that γ-glutamyltransferase was not released. 4. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis under reducing conditions of microvilli revealed 36 polypeptide bands, 12 of which contained carbohydrate. A band of apparent Mr 130 000 was labelled with [3H]di-isopropylphosphorofluoridate and hence identified as dipeptidyl peptidase IV. 5. Antibodies raised to human kidney microvilli produced 11 precipitates with detergent solubilized proteins and six with papain released proteins. Several of the precipitates were identified histochemically. 6. Microvilli prepared from human kidney are very similar to microvilli from pig and rabbit kidney with respect to enzymology, response to papain treatment, sodium dodecyl sulphate-polyacrylamide gel patterns and immunochemistry.

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Proteins of the kidney microvillar membrane. Biosynthesis of endopeptidase-24.11, dipeptidylpeptidase IV and aminopeptidases N and A in pig kidney slices

Biochemical Journal ◽

10.1042/bj2240549 ◽

1984 ◽

Vol 224 (2) ◽

pp. 549-558 ◽

Cited By ~ 21

Author(s):

J R Stewart ◽

A J Kenny

Keyword(s):

Renal Cortex ◽

Polyacrylamide Gel Electrophoresis ◽

Sodium Dodecyl ◽

Dipeptidyl Peptidase ◽

Dipeptidyl Peptidase Iv ◽

Chase Period ◽

Pig Kidney ◽

Endopeptidase 24.11 ◽

Membrane Compartments ◽

Aminopeptidase A

An organ culture employing slices of renal-cortex tissue from piglets of the Yucatan strain was used to study the biogenesis of four microvillar peptidases: endopeptidase-24.11 (EC 3.4.24.11), dipeptidyl peptidase IV (EC 3.4.14.5), aminopeptidase N (EC 3.4.11.2) and aminopeptidase A (EC 3.4.11.7). The viability of the culture system was confirmed by the preservation of ultrastructural integrity and by an unchanged uptake of [3H]alanine into cells during the period of the experiments. After labelling with [35S]methionine, treatment with Mg2+ yielded two fractions, one containing microvilli and another, the Mg2+ pellet, containing intracellular and basolateral membranes. The labelled forms of the peptidases, isolated by immunoprecipitation, were analysed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and fluorography. The Mg2+ pellet contained the earliest detectable forms of the enzymes. In each case, a polypeptide of lower Mr than the mature form and sensitive to treatment with endo-beta-N-acetylglucosaminidase H was the first form to be detected. These high-mannose forms were followed, about 30 min after the pulse, by a complex glycosylated form of higher Mr. Only the latter form was observed in microvilli and then only after 90 min of the chase period. A quantitative study of dipeptidyl peptidase IV showed that the forms observed in the Mg2+ pellet were precursors of those in the microvillar fraction. No labelled forms were observed in the cytosol. All four peptidases were thus synthesized within membrane compartments and glycosylated in two steps before assembly in microvilli.

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Inhibition of cysteine proteinases and dipeptidyl peptidase I by egg-white cystatin

Biochemical Journal ◽

10.1042/bj2230245 ◽

1984 ◽

Vol 223 (1) ◽

pp. 245-253 ◽

Cited By ~ 109

Author(s):

M J H Nicklin ◽

A J Barrett

Keyword(s):

Cathepsin B ◽

Bond Cleavage ◽

Polyacrylamide Gel Electrophoresis ◽

Sodium Dodecyl ◽

Dipeptidyl Peptidase ◽

Egg White ◽

Reversible Inhibitor ◽

Cysteine Proteinases ◽

Peptide Bond Cleavage ◽

Specific Oxidation

The interactions between egg-white cystatin and the cysteine proteinases papain, human cathepsin B and bovine dipeptidyl peptidase I were studied. Cystatin was shown to be a competitive reversible inhibitor of cathepsin B (Ki 1.7 nM, k-1 about 2.3×10(-3) s-1). The inhibition of dipeptidyl peptidase I was shown to be reversible (Ki(app.) 0.22 nM, k-1 about 2.2×10(-3) s-1). Cystatin bound papain too tightly for Ki to be determined, but an upper limit of 5 pM was estimated. The association was a second-order process, with k+1 1.0×10(7) M-1×s-1. Papain was shown to form equimolar complexes with cystatin. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of complexes formed between papain or cathepsin B and an excess of cystatin showed no peptide bond cleavage after incubation for 72 h. The reaction of the active-site thiol group of papain with 5,5′-dithiobis-(2-nitrobenzoic acid) at pH 8 and 2,2′-dithiobispyridine at pH 4 was blocked by complex-formation. Dipeptidyl peptidase I and papain were found to compete for binding to cystatin, contrary to a previous report. The two major isoelectric forms of cystatin were found to have similar specific inhibitory activities for papain, and similar affinities for papain, cathepsin B and dipeptidyl peptidase I. This, together with specific oxidation of the N-terminal serine residue with periodate, showed the N-terminal amino group of cystatin 1 to be unimportant for inhibition. General citraconylation of amino groups resulted in a large decrease in the affinity of cystatin for dipeptidyl peptidase I. It is concluded that the interaction of cystatin with cysteine proteinases has many characteristics similar to those of an inhibitor such as aprotinin with serine proteinases.

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Biochemical characterization including amino acid and carbohydrate compositions of canine and human brain Thy-1 antigen

Biochemical Journal ◽

10.1042/bj1970629 ◽

1981 ◽

Vol 197 (3) ◽

pp. 629-636 ◽

Cited By ~ 19

Author(s):

J L McKenzie ◽

A K Allen ◽

J W Fabre

Keyword(s):

Monoclonal Antibody ◽

Amino Acid ◽

Human Brain ◽

Affinity Chromatography ◽

Gel Electrophoresis ◽

Polyacrylamide Gel Electrophoresis ◽

Sodium Dodecyl ◽

Gel Filtration ◽

Antibody Affinity ◽

Lentil Lectin

Human and canine brain Thy-1 antigens were solubilized in deoxycholate and antigen activity was followed both by conventional absorbed anti-brain xenosera of proven specificity and by mouse monoclonal antibodies to canine and human Thy-1. It is shown that greater than 80% of Thy-1 activity in the dog and man binds to lentil lectin, that the mobility on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of canine and human Thy-1 is identical with that of rat Thy-1 and that the Stokes radius in deoxycholate of canine and human brain Thy-1 is 3.0 nm and 3.25 nm respectively. Both lentil lectin affinity chromatography followed by gel-filtration chromatography on the one hand and monoclonal antibody affinity chromatography on the other gave high degrees of purification of the brain Thy-1 molecule in the dog and man, resulting in single bands staining for both protein and carbohydrate on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis (except for a slight contaminant of higher molecular weight staining for protein but not carbohydrate with human Thy-1 purified by lentil lectin and gel-filtration chromatography). Analysis of canine and human brain Thy-1 purified by monoclonal antibody affinity chromatography with additional gel filtration through Sephadex G-200 showed that these molecules had respectively 38% and 36% carbohydrate. The amino acid and carbohydrate compositions were similar to those previously reported for Thy-1 of the rat and mouse, the main point of interest being the presence in canine and human brain Thy-1 of N-acetylgalactosamine, which has been reported in rat and mouse brain Thy-1 but not in Thy-1 from other tissues.

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