Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The activities of 30 different lysosomal enzymes were determined in vitro in the presence of the sulphated glycosaminoglycans, heparin and chondroitin sulphate, all the enzymes being measured on a density-gradient-purified lysosomal fraction. 2. Each enzyme was studied as a function of the pH of the incubation medium. In general the presence of sulphated glycosaminoglycans induced a strong pH-dependent inhibition of lysosomal enzymes at pH values lower than 5.0, with full activity at higher pH values. However, in the particular case of lysozyme and phospholipase A2 the heparin-induced inhibition was maintained in the pH range 4.0-7.0. 3. For certain enzymes, such as acid beta-glycerophosphatase, alpha-galactosidase, acid lipase, lysozyme and phospholipase A2, the pH-dependent behaviour obtained in the presence of heparin was quite different to that obtained with chondroitin sulphate, suggesting the existence of physicochemical characteristic factors playing a role in the intermolecular interaction for each of the sulphated glycosaminoglycans studied. 4. Except in the particular case of peroxidase activity, in all other lysosomal enzymes measured the glycosaminoglycan-enzyme complex formation was a temperature-and time-independent phenomenon. 5. The effects of the ionic strength and pH on this intermolecular interaction reinforce the concept of an electrostatic reversible interaction between anionic groups of the glycosaminoglycans and cationic groups on the enzyme molecule. 6. As leucocytic primary lysosomes have a very acid intragranular pH and large amounts of chondroitin sulphate, we propose that this glycosaminoglycan might act as molecular regulator of leucocytic activity, by inhibiting lysosomal enzymes when the intragranular pH is below the pI of lysosomal enzymes. This fact, plus the intravacuolar pH changes described during the phagocytic process, might explain the unresponsiveness of lysosomal enzymes against each other existing in primary lysosomes as well as its full activation at pH values occurring in secondary lysosomes during the phagocytic process.
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PMID:Physicochemical characteristics of the glycosaminoglycan-lysosomal enzyme interaction in vitro. A model of control of leucocytic lysosomal activity. 1 48

The determination of enzyme levels in cell-free amniotic fluid has proven useful in assessing fetal maturity and fetal well being, and is being utilized for the prenatal diagnosis of genetic disorders. The activities of amylase, alpha-galactosidase, phosphatidic acid phosphohydrolase, lysozyme and heat-stable alkaline phosphatase in amniotic fluid increase with gestational age and have an established relationship to fetal maturity. The ratio of amniotic fluid diamine oxidase activity to maternal serum activity (amniotic DAO/serum DAO) may be used as an indicator of the degree of rhesus isoimmunization after 28 weeks gestation. Creatine phosphokinase in amniotic fluid is elevated in cases of in utero fetal death and is of diagnostic significance. The prenatal diagnosis of Tay-Sachs disease, Sandhoff's disease, fucosidosis, GM1-gangliosidosis and I-cell disease have been made from the analysis of appropriate enzymes in cell-free amniotic fluid.
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PMID:Enzymes in amniotic fluid. 19 24