Enzymatic Reaction (image will open in a new window)
Molecular weight: Trypsinogen: 24,000 (Walsh and Neurath 1964).
Composition: Trypsinogen has been shown to have certain intrinsic activity. See Knights and Light (1974) for further references. It is usually considered, however, as the inactive precursor of trypsin which may be activated by removal of a terminal hexapeptide to yield single-chain β-trypsin. Subsequent limited autolysis produces other active forms having two or more peptide chains bound by disulfide bonds. The predominant forms are α-trypsin, having two peptide chains and β-, a single chain. Different activity and thermal stability are shown by α- and β-trypsin.
Isoelectric point: Trypsinogen: pH 9.3 (Walsh and Neurath 1964).
Activators: The rate of trypsinogen conversion is enhanced by using lanthanide in place of calcium ions (Gomez et al. 1974).
Stabilizers: Calcium ion retards trypsin autolysis and promotes activation of trypsinogen. Sipos and Merkel (1970) have reported on the calcium-trypsin complex. See also Griffiths and Brechner (1973).