Article synthesizing and testing the synthetic peptide AKRRRLSSLRASTSKSESSQK (56-21) which corresponds to the carboxyl-terminal 21 amino acids of human ribosomal protein S6 as a substrate for S6/H4 kinase purified from human placenta. The data suggests that multiple S6 kinases may be required to phosphorylate S6 at all five sites which are modified in vivo.

Article isolating a gene encoding cytosolic bate peroxidase (ApxI) from pea (Pisum sativum L.) and determining its nucleotide sequence.

Article describing a novel S6 kinase isolated from human placenta which autoactivates through autophosphorylation in vitro. The data supports the hypothesis that this previously uncharacterized S6 kinase belongs to a unique family of protein kinases which utilize autophosphorylation as part of their in vivo activation mechanism.

Article proposing a model in which phosphorylation of sites 1 and 2 occurs sequentially. The model proposes that trypsin treatment of the inactive holoenzyme removes an inhibitory rac-binding domain which blocks MgATP access to the catalytic site. The pseudosubstrate domain at site 1 is autophosphorylated and subsequent bimolecular autophosphorylation at site 2 fully opens the catalytic site.