scholarly journals Characterization of proteoglycan degradation by calpain

1992 ◽  
Vol 285 (3) ◽  
pp. 857-862 ◽  
Author(s):  
K Suzuki ◽  
K Shimizu ◽  
T Hamamoto ◽  
Y Nakagawa ◽  
T Murachi ◽  
...  
Keyword(s):  
Core Protein ◽  
Cysteine Proteinase ◽  
Limited Proteolysis ◽  
Side Chains ◽  
Proteoglycan Degradation ◽  
Cartilage Proteoglycans ◽  
Neutral Conditions ◽  
Calpain Ii ◽  
Enzyme Ratio

Degradation of cartilage proteoglycans was investigated under neutral conditions (pH 7.5) by using pig kidney calpain II (EC 3.4.22.17; Ca(2+)-dependent cysteine proteinase). Aggregate and monomer degradation reached a maximum in 5 min at 30 degrees C when the substrate/enzyme ratio was less than 1000:1. The mode of degradation was limited proteolysis of the core protein; the size of the products was larger than that of papain-digested products and comparable with that of trypsin-digested products. The hyaluronic acid-binding region was lost from the major glycosaminoglycan-bearing region after incubation with calpain II. Calpains thus may affect the form of proteoglycans in connective tissue. Ca(2+)-dependent proteoglycan degradation was unique in that proteoglycans adsorb large amounts of Ca2+ ions rapidly before activation of calpain II: 1 mg of pig cartilage proteoglycan monomer adsorbed 1.3-1.6 mu equiv. of Ca2+ ions before activation of calpain II, which corresponds to half the sum of anion groups in glycosaminoglycan side chains. This adsorption of Ca2+ was lost after solvolysis of proteoglycan monomer with methanol/50 mM-HCl, which was used to desulphate glycosaminoglycans. Therefore cartilage proteoglycans are not merely the substrates of proteolysis, but they may regulate the activation of Ca(2+)-dependent enzymes including calpains through tight chelation of Ca2+ ions between glycosaminoglycan side chains.

scholarly journals Catabolism of aggrecan, decorin and biglycan in tendon

2000 ◽  
Vol 350 (1) ◽  
pp. 181-188 ◽  
Author(s):  
Sarah G. REES ◽  
Carl R. FLANNERY ◽  
Chris B. LITTLE ◽  
Clare E. HUGHES ◽  
Bruce CATERSON ◽  
...  
Keyword(s):  
Culture Medium ◽  
Core Protein ◽  
Degradation Products ◽  
Chondroitin Sulphate ◽  
Expression Patterns ◽  
Collagen Matrix ◽  
Pcr Analysis ◽  
Age Related ◽  
Proteoglycan Degradation

We have examined the catabolism of the proteoglycans aggrecan, decorin and biglycan in fresh tendon samples and in explant cultures of tissue from the tensional and compressed regions of young and mature bovine tendons. A panel of well-characterized antibodies that recognize glycosaminoglycan or protein (linear or neoepitope) sequences was used to detect proteoglycans and proteoglycan degradation products that were both retained within the tissue and released into the culture medium. In addition, a reverse-transcriptase-mediated PCR analysis was used to examine the mRNA expression patterns of tendon proteoglycans and aggrecanases. The results of this study indicate a major role for aggrecanase(s) in the catabolism of aggrecan in bovine tendon. The study also provides a characterization of glycosaminoglycan epitopes associated with the proteoglycans of tendon, illustrating age-related changes in the isomers of chondroitin sulphate disaccharides that remain attached to the core protein glycosaminoglycan linkage region after digestion with chondroitinase ABC. Evidence for a rapid turnover of the small proteoglycans decorin and biglycan was also observed, indicating additional molecular pathways that might compromise the integrity of the collagen matrix and potentially contribute to tendon dysfunction after injury and during disease.

scholarly journals Calpain inhibition by peptide epoxides

1985 ◽  
Vol 230 (2) ◽  
pp. 509-516 ◽  
Author(s):  
C Parkes ◽  
A A Kembhavi ◽  
A J Barrett
Keyword(s):  
Smooth Muscle ◽  
Active Site ◽  
Rate Constants ◽  
Cysteine Proteinase ◽  
Limited Proteolysis ◽  
Enzymic Activity ◽  
Isoelectric Precipitation ◽  
Structural Analogues ◽  
Calpain Inhibition ◽  
Calpain Ii

A Ca2+-activated cysteine proteinase (calpain II) was purified from chicken gizzard smooth muscle by use of isoelectric precipitation, (NH4)2SO4 fractionation, chromatography on DEAE-Sepharose CL-6B, Reactive-Red 120-agarose and Mono Q. The apparent second-order rate constants for the inactivation of calpain by a series of structural analogues of L-3-carboxy-trans-2, 3-epoxypropionyl-leucylamido-(4-guanidino)butane (E-64) were determined. The fastest rate of inactivation was observed with L-3-carboxy-trans-2, 3-epoxypropionyl-leucylamido-(4-benzyloxy-carbonylamino)buta ne. It was possible to determine the active-site molarity of solutions of calpain by titration with E-64. When incubated with Ca2+, calpain underwent several steps of intermolecular limited proteolysis, via multiple pathways, followed by a slower loss of enzymic activity. The proteolytic steps preceding the loss of activity did not affect the rates of reaction of calpain with E-64 analogues.

scholarly journals The identification and characterization of two populations of aggregating proteoglycans of high buoyant density isolated from post-natal human articular cartilages of different ages

1987 ◽  
Vol 248 (3) ◽  
pp. 735-740 ◽  
Author(s):  
C Webber ◽  
T T Glant ◽  
P J Roughley ◽  
A R Poole
Keyword(s):  
Hyaluronic Acid ◽  
Core Protein ◽  
Chondroitin Sulphate ◽  
Buoyant Density ◽  
Human Articular Cartilage ◽  
Keratan Sulphate ◽  
Different Ages ◽  
Cartilage Proteoglycans ◽  
Two Populations

After chromatography on Sepharose CL-2B under associative conditions, high-buoyant-density human articular-cartilage proteoglycans were analysed biochemically and by radioimmunoassay with monoclonal antibodies to a core-protein-related epitope and to keratan sulphate. An examination of proteoglycans from individuals of different ages revealed the presence at 1 year of mainly a single polydisperse population containing chondroitin sulphate (uronic acid) and keratan sulphate. From 4 years onwards a smaller keratan sulphate-rich and chondroitin sulphate-deficient population appears in increasing amounts until 15 years. At the same time the larger population shows a progressive decrease in size from 1 year onward. By 23 years and after the proportion of keratan sulphate in the larger chondroitin sulphate-rich proteoglycan increases. Both adult proteoglycan populations are shown immunologically to aggregate with hyaluronic acid, with the smaller showing a greater degree of interaction. The larger population is richer in serine and glycine, and the smaller population contains more glutamic acid/glutamine, alanine, phenylalanine, lysine and arginine; its protein content is also higher. Whether the larger post-natal population represents a different gene product from the single polydisperse population found in the human fetus, which has a different amino acid composition, remains to be established. The smaller population, which represents approximately one-third the mass of the larger population in the adult, may represent a degradation product of the larger population, in which the hyaluronic acid-binding region and keratan sulphate-rich region are conserved.

Preparation and characterization of glycopolymers with biphenyl spacers via Suzuki coupling reaction

2021 ◽  
Author(s):  
Hirokazu Seto ◽  
Takumi Tono ◽  
Akiko Nagaoka ◽  
Mai Yamamoto ◽  
Yumiko Hirohashi ◽  
...  
Keyword(s):  
Coupling Reaction ◽  
Suzuki Coupling ◽  
Side Chains ◽  
Suzuki Coupling Reaction ◽  
Reactant Concentration

Poly(vinylbiphenyl)s bearing glycoside ligands at the side chains were prepared using the Suzuku coupling reaction. Effects of glycoside reactant concentration, halide species, glycoside species, and catalyst species on the incorporation...

Effect of polycyclosilane microstructure on thermal properties

2021 ◽  
Author(s):  
Qifeng Jiang ◽  
Sydnee Wong ◽  
Rebekka S Klausen
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Thermal Characterization ◽  
Side Chains ◽  
Phase Properties

Thermal characterization of polysilanes has focused on the influence of organic side chains, whereas little is understood about the influence of silane backbone microstructure on thermal stability, phase properties, and...

Sign in / Sign up

Export Citation Format

Share Document