Search results for "Cathepsins"

?-Glucuronidase activity in trained red and white skeletal muscle of mice

1978

We studied the effects of prolonged running exercise (5 days a week, 1.5 h per day at a speed of 17.6 m/min) on the activity of some acid hydrolases (beta-glucuronidase, beta-N-acetylglucosaminidase, acid phosphatase and cathepsin D) and three enzymes of energy metabolism (cytochrome c oxidase, lactate dehydrogenase and creatine kinase) in the distal and in the proximal, the predominantly white and red parts, respectively, of the vastus lateralis-muscle from mice. The acid hydrolase activity levels were 1.24--1.69 higher in untrained red muscle compared to untrained white muscle. The light training applied increased the activity of beta-glucuronidase in both red and white muscle. No other s…

Acid hydrolase activity in red and white skeletal muscle of mice during a two-week period following exhausting exercise

1978

The activities of beta-glucuronidase, beta-N-acetylglucosaminidase, arylsulphatase, ribonuclease, p-nitrophenylphosphatase, and malate dehydrogenase together with protein content were assayed from representative mixed (m. rectus femoris), predominantly red (proximal heads of m. vastus lateralis, m.v. medius and m. v. intermedius), and predominantly white (distal head of m. vastus lateralis) muscle homogenates of mice during a two-week period following one single exposure to exhausting intermittent running on a treadmill. The activities of cathepsin D and beta-glycerophosphatase were assayed from mixed muscle only. In all three muscle types, particularly in red muscle, the activities of beta…

Acid hydrolase activities in mouse cardiac and skeletal muscle following exhaustive exercise

1981

Acid hydrolase activities in skeletal and cardiac muscle were studied 5, 10 and 20 days after exhaustive intermittent running by untrained and endurance-trained mice. Exhaustion increased the activities of cathepsin D, beta-glucuronidase and ribonuclease, but not that of p-nitrophenylphosphatase in skeletal muscle of untrained mice. Activities were highest on the fifth day after exhaustion and decreased during the following two weeks. More intensive loading produced no changes in acid hydrolytic capacity in skeletal muscle of endurance-trained mice. Acid hydrolase activities in cardiac muscle of both untrained and trained mice were unaffected by exhaustive running. It is suggested that exha…

Lysosomal changes related to exercise injuries and training-induced protection in mouse skeletal muscle

1984

Three experiments were designed to study the lysosomal changes associated with the development and maintenance of the endurance training induced resistance against exercise injuries in mouse skeletal muscles. The activities of arylsulphatase, cathepsin C, cathepsin D, and beta-glucuronidase were assayed from the red part of mouse quadriceps femoris muscle 4 days after prolonged strenuous running of 4-9 h duration. Exercise injuries were characterized by necrotic fibers and focal inflammation. Strenuous running of untrained mice induced necrotic lesions and a 4-5 fold increase in the activities of lysosomal enzymes. This lysosomal response was considerably reduced already by daily training b…

Enzyme-based biosilica and biocalcite: biomaterials for the future in regenerative medicine

2013

The oldest animals on Earth, sponges, form both the calcareous and the siliceous matrices of their spicules enzymatically. Until recently, it has been neglected that enzymes play crucial roles during formation of these biominerals. This paradigm shift occurred after the discovery that the enzyme silicatein, which catalyzes the polycondensation of silica, and the enzyme carbonic anhydrase (CA), which catalyzes the formation of bicarbonate (HCO3(-)/CaCO3), produce solid amorphous bioglass or biocalcite. This suggests that in mammals, biosilica and biocalcite can act anabolically during hydroxyapatite (HA) synthesis and bone formation. Biosilica and biocalcite are thus promising candidates for…

Bioengineering of the silica-polymerizing enzyme silicatein-alpha for a targeted application to hydroxyapatite.

2009

Since its discovery, numerous biotechnological approaches have aimed to explore the silica-polymerizing catalytic activity of the enzyme silicatein. In vivo, silicatein catalyzes polymerization of amorphous silica nanospheres from soluble precursors. In vitro, it directs the formation of nanostructured biosilica. This is of interest for various applications that strive to benefit from both the advantages of the biological system (i.e., silica synthesis under physiological conditions) and the cell mineralization-stimulating effect of biosilica. However, so far immobilization of silicatein has been hampered by the complex multistep procedure required. In addition, the chemical surface modific…

Biosilica electrically-insulating layers by soft lithography-assisted biomineralisation with recombinant silicatein.

2011

Optical properties of in-vitro biomineralised silica

2012

Silicon is the second most common element on the Earth's crust and its oxide (SiO(2)) the most abundant mineral. Silica and silicates are widely used in medicine and industry as well as in micro- and nano-optics and electronics. However, the fabrication of glass fibres and components requires high temperature and non-physiological conditions, in contrast to biosilica structures in animals and plants. Here, we show for the first time the use of recombinant silicatein-α, the most abundant subunit of sponge proteins catalyzing biosilicification reactions, to direct the formation of optical waveguides in-vitro through soft microlithography. The artificial biosilica fibres mimic the natural spon…

Proteomic identification of protease cleavage sites characterizes prime and non-prime specificity of cysteine cathepsins B, L, and S.

2011

Cysteine cathepsins mediate proteome homeostasis and have pivotal functions in diseases such as cancer. To better understand substrate recognition by cathepsins B, L, and S, we applied proteomic identification of protease cleavage sites (PICS) for simultaneous profiling of prime and non-prime specificity. PICS profiling of cathepsin B endopeptidase specificity highlights strong selectivity for glycine in P3' due to an occluding loop blocking access to the primed subsites. In P1', cathepsin B has a partial preference for phenylalanine, which is not found for cathepsins L and S. Occurrence of P1' phenylalanine often coincides with aromatic residues in P2. For cathepsin L, PICS identifies 845 …

Monitoring the formation of biosilica catalysed by histidine-tagged silicatein.

2004

Surface bound silicatein retains its biocatalytic activity, which was demonstrated by monitoring the immobilisation of silicatein using a histidine-tag chelating anchor and the subsequent biosilicification of SiO(2) on surfaces by surface plasmon resonance spectroscopy, atomic force microscopy and scanning electron microscopy.