Introduction: The Classification of Proteinases

Barrett, Alan J.

doi:10.1002/9780470720585.ch1

Cited by 14 publications

(4 citation statements)

References 36 publications

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“…Matrix proteins can be degraded by four classes of enzymes: cysteine, aspartate-and serine-dependent, and metalloproteinases, each of which is characterized by the amino acid or chemical group in the catalytic site of the enzyme (28). The cysteine and aspartate-dependent proteinases act at low pH, and are primarily intracellular, while metalloproteinases and serine-dependent proteases act extracellularly at neutral pH.…”

Section: Connective Tissue Degradation In Arthritismentioning

confidence: 99%

Matrix Metalloproteinases: Role In Arthritis

Mix²,

2006

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The irreversible destruction of the cartilage, tendon, and bone that comprise synovial joints is the hallmark of both rheumatoid arthritis (RA) and osteoarthritis (OA). While cartilage is made up of proteoglycans and type II collagen, tendon and bone are composed primarily of type I collagen. RA is an autoimmune disease afflicting numerous joints throughout the body; in contrast, OA develops in a small number of joints, usually resulting from chronic overuse or injury. In both diseases, inflammatory cytokines such as interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) stimulate the production of matrix metalloproteinases (MMPs), enzymes that can degrade all components of the extracellular matrix. The collagenases, MMP-1 and MMP-13, have predominant roles in RA and OA because they are rate limiting in the process of collagen degradation. MMP-1 is produced primarily by the synovial cells that line the joints, and MMP-13 is a product of the chondrocytes that reside in the cartilage. In addition to collagen, MMP-13 also degrades the proteoglycan molecule, aggrecan, giving it a dual role in matrix destruction. Expression of other MMPs such as MMP-2, MMP-3 and MMP-9, is also elevated in arthritis and these enzymes degrade non-collagen matrix components of the joints. Significant effort has been expended in attempts to design effective inhibitors of MMP activity and/or synthesis with the goal of curbing connective tissues destruction within the joints. To date, however, no effective clinical inhibitors exist. Increasing our knowledge of the crystal structures of these enzymes and of the signal transduction pathways and molecular mechanisms that control MMP gene expression may provide new opportunities for the development of therapeutics to prevent the joint destruction seen in arthritis.

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Section: Connective Tissue Degradation In Arthritismentioning

confidence: 99%

Matrix Metalloproteinases: Role In Arthritis

Mix²,

2006

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“…These hydrolases are categorized according to their digest sites in proteins, and include endopeptidases (or proteinases), which digest proteins by cleaving internal peptide bonds, and exopeptidases (or proteases), which digest proteins from the N‐ or C‐terminal of proteins. Endopeptidases are further divided into serine proteinases, cysteine proteinases, aspartic proteinases and metallo proteinases, based on the amino acids present in their active centres (Barrett, 1980). Cysteine proteinases contain various proteinases, including cathepsins L, B, H, O, S, T, K, V and F (http://www.expasy.ch/enzyme/enzyme-byclass.html).…”

Section: Introductionmentioning

confidence: 99%

A cathepsin L‐like proteinase is involved in moulting and metamorphosis in Helicoverpa armigera

Wang¹,

Chai²,

et al. 2010

Insect Molecular Biology

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Holometabolous insects undergo larval moulting and metamorphosis within their life cycle. A cDNA encoding the cathepsin L-like proteinase Ha-cathL has been cloned from Helicoverpa armigera. It has a sequence of 1826 bp and encodes a 550-residue protein with a molecular mass of 63 kDa. Northern blot analysis indicated that Ha-cathL is specifically expressed in haemocytes, with increased expression during larval moulting and metamorphosis. In vivo experimentation revealed that Ha-cathL is up-regulated by 20-hydroxyecdysone. Meanwhile, in situ hybridization and immunocytochemistry revealed that Ha-cathL mRNA is mainly expressed in granulocytes and plasmatocytes. Knock down of cathepsin L by RNA interference results in larvae death before pupation or the formation of a chimeric pupa containing a larval head and thorax, abnormal wings and the pupal abdomen. The reason for this is that the affected haemocytes cannot become granulated, and therefore cannot participate in fat body remodelling and wing development. These facts suggest that Ha-cathL is involved in larval moulting and metamorphosis by participating in the functioning of haemocytes.

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“…Since trichomonas extracts may contain proteases, a protease inhibitor was used for an activity free of inhibitory effects from these enzymes. An inhibitor of proteases that does not interfere with the activity of sphingomyelinase was used in this assay [40, 41]. The outcome shows an increase more than 10 times in the SMase activity (Figure 1).…”

Section: Discussionmentioning

confidence: 99%

“…The effect of inhibitors on SMase activity was measured from TE, P30, or S30 fractions in the presence of sodium salt p-chloromercuribenzoate, a protease inhibitor, in a final concentration of 0.1 mM in all fractions [40, 41]. Incubation time was determined by incubation of TE, P30, or S30 assay samples (each containing 400 μ g of total protein) for 0–150 min.…”

Section: Methodsmentioning

confidence: 99%

Sphingomyelinase Activity ofTrichomonas vaginalisExtract and Subfractions

González-Salazar

Garza-González

Hernández-Luna

et al. 2013

BioMed Research International

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Trichomoniasis is one of the most common acute sexually transmitted curable diseases, and it is disseminated worldwide generating more than 170 million cases annually. Trichomonas vaginalis is the parasite that causes trichomoniasis and has the ability to destroy cell monolayers of the vaginal mucosa in vitro. Sphingomyelinases (SMase) are enzymes that catalyze the hydrolysis of sphingomyelin into ceramide and phosphorylcholine. Ceramide appears to be a second messenger lipid in programmed apoptosis, cell differentiation, and cell proliferation. Sphingomyelinase is probably a major source of ceramide in cells. Signal transduction mediated by ceramide leads cells to produce cytokine induced apoptosis during several inflammatory responses. SMase are also relevant toxins in several microorganisms. The main objective of this research is to identify SMase activity of T. vaginalis in the total extract (TE), P30, and S30 subfractions from brooked trophozoites. It was found that these fractions of T. vaginalis have SMase activity, which comes principally from P30 subfraction and was mainly type C. Enzymatic activity of SMase increased linearly with time and is pH dependent with two peaks by pH 5.5 and pH 7.5. The addition of manganese to the reaction mixture increased the SMase activity by 1.97.

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Introduction: The Classification of Proteinases

Cited by 14 publications

References 36 publications

Matrix Metalloproteinases: Role In Arthritis

Matrix Metalloproteinases: Role In Arthritis

A cathepsin L‐like proteinase is involved in moulting and metamorphosis in Helicoverpa armigera

Sphingomyelinase Activity ofTrichomonas vaginalisExtract and Subfractions

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