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Proteolytic enzymes

About: Proteolytic enzymes is a research topic. Over the lifetime, 23096 publications have been published within this topic receiving 835544 citations.


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TL;DR: In this article, the addition of haze-protective factors, yeast mannoproteins, to wines results in decreased particle size of haze, probably by competition with wine proteins for other non-proteinaceous wine components required for the formation of large insoluble aggregations of protein.
Abstract: Slow denaturation of wine proteins is thought to lead to protein aggregation, flocculation into a hazy suspension and formation of precipitates. The majority of wine proteins responsible for haze are grape-derived, have low isoelectric points and molecular weight. They are grape pathogenesis-related (PR) proteins that are expressed throughout the ripening period post veraison, and are highly resistant to low pH and enzymatic or non-enzymatic proteolysis. Protein levels in un-fined white wine differ by variety and range up to 300 mg/L. Infection with some common grapevine pathogens or skin contact, such as occurs during transport of mechanically harvested fruit, results in enhanced concentrations of some PR proteins in juice and wine. Oenological control of protein instability is achieved through adsorption of wine proteins onto bentonite. The adsorption of proteins onto bentonite occurs within several minutes, suggesting that a continuous contacting process could be developed. The addition of proteolytic enzyme during short term heat exposure, to induce PR protein denaturation, showed promise as an alternative to bentonite fining. The addition of haze-protective factors, yeast mannoproteins, to wines results in decreased particle size of haze, probably by competition with wine proteins for other non-proteinaceous wine components required for the formation of large insoluble aggregations of protein. Other wine components likely to influence haze formation are ethanol concentration, pH, metal ions and phenolic compounds.

189 citations

Journal ArticleDOI
TL;DR: It is demonstrated that the VirG protein is phosphorylation by the VirA protein and that the phosphate is directly transferred from the phosphorylated VirA molecule (phosphohistidine) to the Virg protein.
Abstract: Agrobacterium tumefaciens virulence genes are induced by plant signals through the VirA-VirG two-component regulatory system. The VirA protein is a membrane-spanning sensor molecule that possesses an autophosphorylating activity, and the VirG protein is a sequence-specific DNA-binding protein. In this report, we demonstrate that the VirG protein is phosphorylated by the VirA protein and that the phosphate is directly transferred from the phosphorylated VirA molecule (phosphohistidine) to the VirG protein. The chemical stability of the phospho-VirG bond suggested that the VirG protein was phosphorylated at the aspartate and/or glutamate residue. The phosphorylated VirG protein was reduced with tritiated sodium borohydride and subjected to proteolytic digestion with the Achromobacter protease I enzyme. The resulting peptide fragments were separated by C8 reversed-phase high-pressure liquid chromatography, and the tritium-labeled peptide was sequenced. Amino acid sequence data showed that the aspartate residue at position 52 was the only site phosphorylated. Changing this aspartate into asparagine resulted in a nonphosphorylatable and biologically nonfunctional gene product. As a control, a randomly chosen aspartate was changed into an asparagine (position 72), and no effect on its phosphorylation or biological activity was observed. Unlike its homologs, including CheA-CheY, EnvZ-OmpR, and NtrB-NtrC, the phospho-VirG molecule was very stable in vitro. The possible implications of these observations and the function of VirG phosphorylation in vir gene activation are discussed.

189 citations

Journal ArticleDOI
TL;DR: These findings imply that the release of either fibrinopeptide triggers similar modes of aggregation; the intermolecular binding sites can be localized to particular molecular domains.

189 citations

Journal ArticleDOI
TL;DR: This review presents the current knowledge of the biological functions of the individual TTSPs in mouse and human tissue development and disease and indicates aberrant expression of TTSP genes appears to be involved in the aetiology of several human disorders, including cancer.

189 citations

Journal ArticleDOI
TL;DR: It is suggested that serum MMP-9, in particular, could have clinical value in identifying patients at high risk for melanoma progression, and that MMP/MMP-1 and M MP-13 play important roles at different phases of metastatic melanoma spread.
Abstract: Purpose: Matrix metalloproteinases (MMP) are proteolytic enzymes that play an important role in various aspects of cancer progression In the present work, we have studied the prognostic significance of serum levels of gelatinase B (MMP-9), collagenase-1 (MMP-1), and collagenase-3 (MMP-13) in patients with advanced melanoma Experimental Design: Total pretreatment serum levels of MMP-9 in 71 patients and MMP-1 and MMP-13 in 48 patients were determined by an assay system based on ELISA Total MMP levels were also assessed in eight healthy controls The active and latent forms of MMPs were defined by using Western blot analysis and gelatin zymography Results: Patients with high serum levels of MMP-9 (≥3766 ng/mL; n = 19) had significantly poorer overall survival (OS) than patients with lower serum MMP-9 levels ( n = 52; median OS, 291 versus 452 months; P = 0033) High MMP-9 levels were also associated with visceral or bone metastasis ( P = 0027), elevated serum alkaline phosphatase level ( P = 00009), and presence of liver metastases ( P = 0032) Serum levels of MMP-1 and MMP-13 did not correlate with OS MMP-1 and MMP-9 were found mainly in latent forms in serum, whereas the majority of MMP-13 in serum was active (48 kDa) form MMP-13 was found more often in active form in patients (mean, 99% of the total MMP-13 level) than in controls (mean, 84% of the total MMP-13 level; P < 00001) After initiating the therapy, patients with elevated levels of MMP-1 (≥298 ng/mL, n = 10) progressed more rapidly than patients with lower levels (median, 19 versus 35 months; P = 0023) Serum levels of MMP-9 and MMP-13 did not correlate with the time to progression (TTP) In multivariate analysis with age and gender, MMP-9 or MMP-1 turned out to be independent prognostic factors for OS [ P = 0039; hazard ratio (HR), 18; 95% confidence interval (95% CI), 103-33] or TTP ( P = 0023; HR, 27; 95% CI, 115-64), respectively Conclusions: Our findings provide evidence that MMP-1, MMP-9, and MMP-13 play important roles at different phases of metastatic melanoma spread and that serum MMP-9, in particular, could have clinical value in identifying patients at high risk for melanoma progression

189 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202350
2022113
2021358
2020434
2019358
2018472