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CRYSTALLINE TRYPSIN : II. GENERAL PROPERTIES.

J H Northrop1, M Kunitz

  • 1Laboratories of The Rockefeller Institute for Medical Research, Princeton, N. J.

The Journal of General Physiology
|October 30, 2009
PubMed
Summary
This summary is machine-generated.

Researchers isolated a crystalline protein with high tryptic activity from beef pancreas. This stable enzyme effectively digests various proteins and accelerates blood coagulation, offering insights into proteolytic enzymes.

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Area of Science:

  • Biochemistry
  • Enzymology
  • Protein Chemistry

Background:

  • Proteolytic enzymes play crucial roles in biological processes.
  • Characterization of novel enzymes aids in understanding protein digestion and function.
  • Beef pancreas is a known source of digestive enzymes.

Purpose of the Study:

  • To isolate and characterize a crystalline protein with high tryptic activity from beef pancreas.
  • To determine the enzymatic properties and stability of the isolated protein.

Main Methods:

  • Isolation of a crystalline protein from beef pancreas.
  • Assays for proteolytic activity against various substrates (casein, gelatin, edestin, hemoglobin).
  • Determination of physical properties: molecular weight, diffusion coefficient, isoelectric point, optimal pH, and stability.
  • Assessment of cofactor requirements (e.g., enterokinase).

Main Results:

  • A crystalline protein with high tryptic activity was successfully isolated.
  • The protein exhibited constant proteolytic and optical activity, with significant stability.
  • It digested casein, gelatin, edestin, and denatured hemoglobin, but not native hemoglobin.
  • The enzyme accelerated blood coagulation but had minimal effect on milk clotting.
  • Physical characterization revealed a molecular weight of approximately 34,000, a diffusion coefficient, and an isoelectric point between pH 7.0-8.0.
  • Optimal casein digestion occurred at pH 8.0-9.0, with optimal stability at pH 1.8.

Conclusions:

  • The isolated crystalline protein is a potent proteolytic enzyme with significant tryptic activity.
  • Its stability and substrate specificity provide valuable information for biochemical applications.
  • The enzyme's properties suggest a role in protein digestion and potentially hemostasis.