{'fraction_non_alphanumeric': 0.026595744680851064, 'fraction_numerical': 0.013297872340425532, 'mean_word_length': 5.323529411764706, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
The Role of Glycogen Phosphorylase in the Control of Glycolysis during Contractile Activity in the Phasic Adductor Muscle of the Bay Scallop, Argopecten irradians concentricus

Glycogen phosphorylase was purified from the phasic adductor muscle of the bay scallop, Argopecten irradians concentricus. Phosphorylase a was active in the absence of adenosine monophosphate (AMP), whereas the activity of phosphorylase b was dependent on the presence of AMP. Adenosine triphosphate (ATP) inhibited both phosphorylase a and phosphorylase b by reducing the binding capacity for inorganic phosphate (Pi). Both phosphorylase a and phosphorylase b were inhibited by glucose-6-phosphate (G-6-P) at physiological concentrations, but the inhibitory effect was more pronounced in phosphorylase b. The two interconvertible forms showed great differences in their respective binding capacities for Pi. In the presence of ATP (5 mM), the apparent Km of phosphorylase a for Pi (11.5 mM) fell within the physiological range of concentrations of Pi (12 mM), whereas the apparent Km of phosphorylase b for Pi (54.3 mM) was much higher than levels of Pi under resting conditions. The content of phosphorylase a increased from 23.9% under resting conditions to 83.8% after 160 contractions of in vitro preparations of adductor muscle. This conversion results in a dramatic increase in phosphorylase activity and appears to represent the major mechanism in activation of phosphorylase during burst glycogenolysis in this muscle.