Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.11 (CD10)
 9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The extracellular form of pullulanase (EC 3.2.1.41) from Klebsiella aerogenes has been purified to homogeneity by successive chromatography through diethylaminoethyl-cellulose, Sephadex G-200, and 1,6-diaminohexane-Sepharose. In addition, the cell-bound form of pullulanase has been released by the action of a serine endopeptidase obtained from Pronase and purified to apparent homogeneity. Protease-released pullulanase has a slightly larger molecular weight and a specific activity over twice that of the extracellular protein. The properties of each of these forms of pullulanase have been compared with those reported for the detergent-released form. Each form has different features as examined by amino acid composition, specific activity, molecular weight, or inhibition pattern, which distinguish it from the other pullulanases. It is hypothesized that a single gene product consisting of a single polypeptide chain generates these different enzyme forms after selective cleavages by endogenous or applied proteases.
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PMID:Extracellular and protease-released pullulanases. 94 14

Intracellular perfusion of giant axons from Loligo forbesi with a crude protein extract of Pronase dissolved in a KF solution suppresses the process of fast inactivation of the Na conductance (the h-process in the Hodgkin-Huxley terminology). 2. The results with protease inhibitors indicate that the most substrate specific endopeptidase present in pronase, alkaline proteinase b, destroys the h-process. 3. After destruction of the inactivation the conductance rise upon depolarization followed cube law kinetics. Values of the time constant taum before and after destruction of the h-process were very similar. 4. After destruction of the inactivation process the following properties were tested: cation selectivity, instantaneous conductance and internal receptor sites for tetrodotoxin (TTX) and tetraethylammonium (TEA). No detectable changes in selectivity or instantaneous conductance were observed. No internal receptors for TTX affecting the Na conductance were found but a TEA receptor is exposed by the protein hydrolysis. 5. TEA derivatives (triethylammonium, TEA-, with an aliphatic chain, Cn) induce a partial block of the steady-state sodium current and induce a time-dependent blockage of the conductance. 6. The first effect of TEA-Cn could be described in terms of a unimolecular reaction with the following equilibrium constants: 50, 2-5, 1-0, 0-4 and 0-025 mM for TEA-C2, TEA-C4, TEA-C5, TEA-C7 and TEA-C9 respectively. 7. From the dependence of the equilibrium dissociation constant on the length of the alkyl chain we estimated the free-energy change in 560 cal/mole of CH2. The gain in free energy per CH2 group transferred from aqueous medium to the interior of a non-polar medium is 1000 cal. 8. Although with the data at hand it is impossible to propose the amino-acid sequence of the site cleaved by alkaline proteinase b, we propose that an important functional component is arginine (or lysine).
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PMID:Destruction of the sodium conductance inactivation by a specific protease in perfused nerve fibres from Loligo. 99 46