Biochemical Studies on the Shell Gland of Japanese Quail, Coturnix coturnix japonica

Abstract

Pyruvate kinase (EC 2.7.1.40) in Japanese quail shell gland was examined for the multiple components and enzymic properties. Two components were obtained by isoelectric focusing. Isoelectric points of the two components were pH 4.5 (designated SGPK-I) and pH 6.1 (designated SGPK-II), respectively. In the shell gland mucosa, the existence of only SGPK-II was detected. SGPK-I and SGPK-II were eluted from DEAE-cellulose by 0.02M and 0.12M KC1, respectively at pH 7.4 (20mM Tris-HCl). In the absence of fructose-1, 6-diphosphate (FDP), SGPK-I and SGPK-II, showed a sigmoidal response with respect to phosphoenolpyruvate (PEP) concentration, while in the presence of FDP, they both exhibited the Michaelis-Menten type response. Kinetical responses of SGPK-I and SGPK-II were markedly influenced by pH, K + and Mg 2+ concentration even in the presence of FDP. No significant difference in apparent Km value for PEP of the two components was obtained. The inhibition of the two components by ATP was pH-dependent and was reversed by the presence of FDP. The two components from the shell gland were inhibited by Ca 2+ . The inhibition by Ca 2+ was dependent on pH, K + , and Mg 2+ concentration. FDP altered the Km value for PEP several folds smaller, of the two components inhibited by Ca 2+ , but did not change the Vmax. During the egg formation process, the ratio of the summed activity of SGPK-I to that of SGPK-II varied from 0.5 (minimum) to 2.0 (maximum), depending on the position of a developing egg in the oviduct. Physiological significance of the two components in the shell gland is discussed.

Electrofocusing and kinetic studies of adult and embryonic chicken pyruvate kinases

“…Organisms outside of the mammalian family also have multimolecular forms of pyruvate kinase. These include: E. coli (Malcovati et al, 1973); Mucor rouxii (Friedenthal et al, 1973); locust (Bailey and Walker, 1969); oyster (Mustafa and Hochachka, 1971); trout (Somero and Hochachka, 1968); Rana pipiens (Schloen et al, 1974); Xenopus laevis (Ibsen et al, to be published); turtles (Kornecki-Gerrity and Penny, 1974); quail shell gland (Yamada, 1974); pigeon (Gabrielli and Baldi, 1972); and chickens (Cardenas et al, 1975a,b;Strandholm et al, 1975).…”