#Question id: 1257
#Unit 4. Cell Communication and Cell Signaling
Following statements are regarding to protein kinase A which phosphorylates multiple intracellular target proteins expressed in different cell types.
A. Inactive PKA is a tetramer consisting of two regulatory (R) subunits and two catalytic (C) subunits.
B. Each R subunit contains a pseudo-substrate domain whose sequence resembles that of a peptide substrate and binds to the active site in the catalytic domain but is not phosphorylated; thus the pseudo-substrate domain inhibits the activity of the catalytic subunits.
C. active PKA is turned off by binding of cAMP Each R subunit has two distinct cAMP-binding sites, called CNB-A and CNB-B.
D. Binding of cAMP by an R subunit of PKA occurs in a cooperative fashion; that is, binding of the first cAMP molecule to CNB-B increases the Kd for binding of the second cAMP to CNB-A. Thus small changes in the level of cytosolic cAMP can cause proportionately large changes in the number of dissociated C subunits and, hence, in cellular kinase activity.
Which of the following statements are incorrect?
#Question id: 849
#Unit 1. Molecules and their Interaction Relevant to Biology
The rigidity of the peptide unit and the restricted set of allowed phi and psi angles limits the number of structures accessible to the unfolded form sufficiently to allow:-
#Question id: 183
#Unit 1. Molecules and their Interaction Relevant to Biology
At pH 7.0, converting a glutamic acid to gamma-carboxyglutamate, will have what effect on the overall charge of the protein containing it?
#Question id: 2376
#Unit 2. Cellular Organization
Which organelle is composed of cristae and a matrix?
#Question id: 23695
#Unit 13. Methods in Biology