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The effects of trypsin, plasmin, chymotrypsin and thrombin on human heart adenylate cyclase activity
G H Cros1, P A Chaptal, J J Serrano
1Laboratoire de Pharmacodynamie, Faculte de Pharmacie, Montpellier, France.
Insights
Proteases like trypsin and plasmin inhibit human heart adenylate cyclase (HHAC) activity. Chymotrypsin shows a complex effect, stimulating then inhibiting HHAC, suggesting proteases regulate cardiac function.
Area of Science:
- Cardiology
- Biochemistry
- Enzymology
Background:
- Adenylate cyclase is a key enzyme in cardiac function.
- Protease activity can influence cellular processes.
Purpose of the Study:
- To investigate the effects of specific proteases on human heart adenylate cyclase (HHAC) activity.
- To understand the potential role of proteases in regulating cardiac function.
Main Methods:
- Incubation of human heart tissue with varying concentrations of trypsin, plasmin, chymotrypsin, and thrombin.
- Measurement of adenylate cyclase activity using established biochemical assays.
Main Results:
- Trypsin and plasmin demonstrated inhibitory effects on HHAC at higher concentrations.
- Chymotrypsin exhibited a biphasic response: stimulation at moderate concentrations (0.5-10 µg/ml) and inhibition at higher levels.
- Maximal stimulation by chymotrypsin reached 67.2 ± 5.4% at 3 µg/ml.
- Thrombin showed no significant impact on HHAC activity up to 1 mg/ml.
Conclusions:
- Proteases, particularly trypsin, plasmin, and chymotrypsin, can modulate human heart adenylate cyclase activity.
- These findings suggest a regulatory role for proteases in cardiac physiology.
- Further research is warranted to elucidate the precise mechanisms and physiological relevance.
Abstract:
The authors report the effects of four proteases (trypsin, plasmin, chymotrypsin and thrombin) on human heart adenylate cyclase (HHAC) activity. Trypsin and plasmin inhibited HHAC at concentrations higher than 0.3 and 1 microgram/ml, respectively. Chymotrypsin had a biphasic effect, with a stimulation (from 0.5 to 10 micrograms/ml) followed by an inhibition at higher concentrations. Maximal stimulation was obtained at 3 micrograms/ml and averaged 67.2 +/- 5.4%. Thrombin had no significant effect at concentrations up to 1 mg/ml. These data indicate that proteases might regulate HHAC and therefore influence cardiac function.