Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.23.5 (cathepsin D)
 4,130 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of enhancement of enzymatic activity by heating at 56 degrees C or by limited treatment with dimethylsulfoxide, trypsin and cathepsin D on two forms (Mr = 50 kDa and 72 kDa) of human epidermal transglutaminase were studied by immunoblots using rabbit antihuman epidermal transglutaminase. Both 50 kDa and 72 kDa transglutaminase bands were detected without any alteration in the mobility of the transglutaminase bands during activation induced by heating at 56 degrees C or by pretreatment with dimethylsulfoxide. With a preincubation period longer than 60 min, the trypsin pretreated sample showed progressive disappearance of the 72 kDa transglutaminase band in conjunction with the loss of transglutaminase activity. On the other hand, samples preincubated with cathepsin D showed a complete disappearance of the 50 kDa band after 180 min. These studies suggest the different forms of human epidermal transglutaminase may regulate enzyme activity each other during normal epidermal differentiation.
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PMID:Alteration of human epidermal transglutaminase during its activation. 198 21

The activity of crude human epidermal transglutaminase was enhanced remarkably following 24 hr preincubation at low pH (pH 4.5), whereas the pure human epidermal transglutaminase did not show enhancement of enzyme activity at low pHs. Preincubation of pure transglutaminase with rat liver lysosomal fractions (100 microgram/ml) caused a time-dependent enhancement of activity at pH 4.5, up to 4.5 times of the initial activity. This enhancement was specific for lysosomal fractions among the several rat liver subcellular fractions tested. The activity of purified transglutaminase stimulated by lysosomal fractions was inhibited by pepstatin (50 microgram/ml), chymostatin (50 microgram/ml) and EDTA (1 mM). Preincubation of purified transglutaminase with 5 to 100 microgram/ml cathepsin D caused a time-dependent enhancement of activity up to 9.5-fold over control. This enhancement was specific for cathepsin D among the several lysosomal enzymes tested. These in vitro observations suggest possible activation mechanisms of epidermal transglutaminase in vivo. Epidermal transglutaminase may be activated by lysosomal acid proteinases, such as cathepsin B1 and cathepsin D, which are released and activated during the autolytic stages in granular layer in epidermis.
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PMID:Mechanism of regulation of human epidermal transglutaminase. 611 35