Characterization of purified starch phosphorylase from mature banana (Musa paradisiaca) leaves
Kumar, A.; Sanwal, G.G.
Indian Journal of Biochemistry and Biophysics 18(6): 421-424
1981
ISSN/ISBN: 0301-1208 PMID: 7333629 Document Number: 169723
Starch phosphorylase purified from mature banana (M. paradisiaca) leaves contains 4 identical polypeptide chains of MW 55,000. Pyridoxal-5'-phosphate does not appear to be a prosthetic group of the enzyme. Phosphate could not be demonstrated in the enzyme protein showing absence of serine phosphate. Four SH groups are present per mole of the enzyme. Of the various amino acids tested, only aromatic amino acids inhibited enzyme activity. ADP, AMP and 3',5'-cyclic AMP were devoid of any effect on the enzyme activity but ATP was a powerful inhibitor. ADP glucose and UDP-glucose also inhibited the enzyme activity. p-Chloromercuric benzoate also exhibited inhibitory effect which can be reversed by excess of 2-mercaptoethanol.