Sulfhydryl Group of Muscle Phosphorylase
Kudo, A.; Shukuya, R.
Journal of Biochemistry 55: 254-259
ISSN/ISBN: 0021-924X PMID: 14162506 Accession: 025611505
Sulfhydryl groups of phosphorylase a are classified into 2 types in their reactivity with p-chloromercuribenzoate; one reacts rapidly, the other slowly. Inhibition of phosphorylase a activity by p-chloromer-curibenzoate does not proceed similarly to the rate of mercaptide formation. N-ethyl maleimide binds with 4 of 18 sulfhydryl groups of phosphorylase a and does not affect the enzyme activity. Adenylic acid protects phosphorylase a from the inhibition by p-chloromercuri-benzoate. Adenylic acid and pyridoxal 5-phosphate are effective in preventing the inactivation of phosphorylase a by x-ray irradiation.