Evidence for the selective release of lysosomal proteinases in fasted rabbits

Regulation of Fructose‐Bisphosphatase Activity

“…The average values of the dissociation constants for the second and third sets of sites were approximately 0.4 and 1.5 p M , respectively. Zn2+ has also been shown to bind to Fru-P2ase from rabbit liver (Benkovic et al, 1978a;Pontremoli et al, 1978a) and rabbit muscle (Pontremoli et al, 1979b;Ikeda et al, 1980). A comparison of the kinetic and binding data of Zn2+ for liver Fru-P,ase, reported from various laboratories, is given in Table IV.…”

“…(1977) observed that rat liver Fru-P2ase contained 12 binding sites for Zn2+ per molecule, or 3 binding sites per subunit, as determined by gel filtration and by precipitation of an insoluble ZnZ+ enzyme complex ( Table IV). The first set of (2) References indicated by number in parentheses: (1) Tejwani et al, 1976b; ( 2 ) Benkovic et al, 1978a; (3) Pontremoli et al, 1978a; (4) Pontremoli et al, 1979a;(5) Pedrosa et al, 1977. 'The enzyme assayed at neutral pH.…”

“…A comparison of the kinetic and binding data of Zn2+ for liver Fru-P,ase, reported from various laboratories, is given in Table IV. Pontremoli et al (1978a) reported binding of 12 moles of Zn2+ per mole of rabbit liver enzyme, presumably 3 molecules per subunit. They also reported the presence of about 2 equiv Znz'/mole in the purified preparation of Fru-P,ase.…”

Fructose 1, 6‐Bisphosphatase: Properties of the Neutral Enzyme and its Modification by Proteolytic Enzymes

“…More detailed studies of the effect of .proteolytic enzymes on the activity and structure of Fru-P,ase have been carried out with subtilisin (21,(44)(45)(46). The changes in activity were similar to those produced by digestion with papain at pH 4.8, namely a four-to six-fold increase in activity measured at p H 9.2, followed by a more gradual decrease in activity at pH 7.5 (Fig.…”

Variations through the day of hepatic and muscular cathepsin A (carboxypeptidase A;EC3.4.12.2), C (dipeptidyl peptidase;EC3.4.14.1) and D (endopeptidase D;EC3.4.23.5) activities and fee amino acids of blood in rats: influence of feeding schedule

“…This latter phenomenon and the reduced food intake during the light period induced a decrease in several free essential amino acids of blood. This decrease was enhanced by the occurrence of higher protein synthesis in the muscle (Rebolledo & Gagliardino, 1971 ; Obled et a/. 1975).…”