What is the condition under which an enzyme is defined as having a “ping-pong”

What is the condition under which an enzyme is defined as having a “ping-pong” mechanism?
A.  Enzyme (or enzyme/prosthetic group) is modified by substrate
B.  The enzyme has a dissociable coenzyme
C.  The first substrate on and the last product off show competitive binding
D.  The reaction is bimolecular
E.  The two substrates bind in a random order


A derivative of thiamine participates as a coenzyme in
A.  the conversion of pyruvate to oxaloacetate.
B.  reactions involving the decarboxylation of alpha-keto acids.
C.  the conversions of glucose to glucuronic acid.
D.  the transamination of alpha-amino acids.
E.  the conversion of methylmalonyl-CoA to succinyl-CoA.


Considering the active site of serine protease enzymes, a fair generalization is that:
A.  Nearly all of the amino acid R-groups of the protein must directly participate in catalysis.
B.  All of the amino acid residues which are involved in the active site are adjacent because they are located on the same short stretch of the polypeptide chain.
C.  The conformation of the active site region does not exist at all until the substrate is bound to the enzyme.
D.  The amino acid residues which form the active site are in close proximity because of the specific three-dimensional shape the protein adopts in its native state.
E.  Only one amino acid residue is involved in the active site.