How is ATPase activity measured?
A common way to determine ATPase activity is to measure the liberation of inorganic phosphate arising from hydrolysis of ATP by colorimetric methods, based on ANSA (anilino-naphthalene sulfonate) reaction after ammonium phosphate molybdate precipitation [1], staining with Baginski reagents [2], or malachite green [3].
How do you analyze enzyme activity?
Enzyme activity = moles of substrate converted per unit time = rate × reaction volume. Enzyme activity is a measure of the quantity of active enzyme present and is thus dependent on conditions, which should be specified.
Which has ATPase activity?
Myosins are molecular motors possessing ATPase activity. There are many types of myosins differentially expressed in development and specific tissue type. Myosin II (conventional myosin) is the main myosin responsible for contractility of muscles and non-muscle cells.
How is ATP hydrolysis measured?
ATP hydrolysis yields inorganic phosphate (Pi), which can be measured by a simple colorimetric reaction. The amount of Pi liberated is directly proportional to the activity of the transporter.
What is ATPase used for?
ATPases are a group of enzymes that catalyze the hydrolysis of a phosphate bond in adenosine triphosphate (ATP) to form adenosine diphosphate (ADP). They harness the energy released from the breakdown of the phosphate bond and utilize it to perform other cellular reactions.
What is the function of ATPase complex?
The function of ATP synthase is to synthesize ATP from ADP and inorganic phosphate (Pi) in the F1 sector. This is possible due to energy derived from a gradient of protons which cross the inner mitochondrial membrane from the intermembrane space into the matrix through the Fo portion of the enzyme.
How do you know if an enzyme is active?
If the substrate is present, the enzyme will do its job. Other enzymes have to be made active. These enzymes aren’t lazy, they are just tightly regulated by molecules called effectors or in other ways that will be described. If an effector is required to regulate an enzyme, the enzyme is an allosteric enzyme.
Why do we measure enzyme activity?
The objective of measuring enzyme activity is normally to determine the amount of enzyme present under defined conditions, so that activity can be compared between one sample and another, and between one laboratory and another.
Which muscle protein has ATPase activity?
myosin ATPase
Skeletal muscles are composed of different fiber types. Based on their actin-activated myosin ATPase activity, they can be classified into type I (slow) and type II (fast) fiber types [25]. Myosin ATPase activity is positively correlated with muscle contraction velocity.
Which part of myosin has ATPase activity?
Short arm of heavy meromyosin.
How do you stop a ATPase reaction?
Add a trace amount (< 1 nM) of 32P-γ-ATP to initiate the ATPase reaction. At various time points, stop the reaction by adding 1 μL of reaction mixture to an equal volume of quench.
What is mitochondrial ATPase?
Mitochondria are known as the powerhouses of the cell. The F1Fo-ATP synthase of the mitochondrial inner membrane produces the bulk of cellular ATP. The respiratory chain complexes pump protons across the inner membrane into the intermembrane space and thereby generate a proton-motive force that drives the ATP synthase.