Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.27 (thermolysin)
 1,894 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human and rabbit kidney and urine contain an inactive form of kallikrein. Studies on the mRNA sequence suggested that the active form of the enzyme and the propeptide are linked by a peptide bond between a basic and hydrophobic amino acid. We studied the activation of prokallikrein by serine proteases and a neutral metalloproteinase, thermolysin, because serine proteases cleave the peptide chain after a basic amino acid and thermolysin before a hydrophobic amino acid. The activity of kallikrein was measured by RIA and with a fluorogenic peptide substrate. Trypsin was used as a standard reference activator. We found that human plasmin and plasminogen, activated by urokinase, activate prokallikrein. Pronase coupled to Sepharose also enhanced the activity of the renal kallikrein zymogen. On a molar basis, thermolysin was a more effective activator of prokallikrein than trypsin. The activation by thermolysin was blocked by the inhibitor phosphoramidon, but not by DFP or SBTI. These experiments indicate that, in addition to serine proteases, neutral metalloproteases of tissues may activate prokallikrein.
 ...
PMID:Activation of human and rabbit prokallikrein by serine and metalloproteases. 315 29

Neuropathy target esterase (NTE) in hen brain membranes can be labelled with tritiated di-isopropylfluorophosphate ([3H]DFP) and appears to be associated with a 155-kDa polypeptide. Using preparative SDS-PAGE, we have obtained preparations in which [3H]DFP-labelled NTE comprises 2% of the total protein. Further purification of the 155-kDa polypeptide has proved difficult. We therefore attempted to use proteases to excise smaller [3H]DFP-labelled fragments which might be more amenable to fractionation. V8 protease treatment generated a labelled fragment of about 16 kDa which could be fractionated on SDS-PAGE and contained tritium attached to both site X (putatively the active site serine) and site Z (the residue to which an isopropyl moiety is transferred during aging of [3H]DFP-inhibited NTE). Papain and thermolysin treatments generated a small labelled peptide (< 10 kDa) which could be fractionated on reverse-phase HPLC and in which tritium was attached to site X but not site Z. N-terminal sequencing of the thermolysin-generated peptide fraction indicated sample heterogeneity but also suggested that the active site of NTE may contain the serine esterase consensus sequence: Gly-Glu-Ser-Xxx-Gly.
 ...
PMID:Molecular characterisation of neuropathy target esterase: proteolysis of the [3H]DFP-labelled polypeptide. 834 93