My early work was in the field of protein synthesis, concentrating on the aminoacyl-tRNA synthetases and the elongation factors that participate in that process. Our work contributed to clarify the stepwise mechanism of the reaction catalyzed by the aminoacyl-tRNA synthetases and the involvement of GTP in the function of EF-Tu in bacteria or EF1 in eukaryotes in bringing the aminoacyl-tRNAs to the elongating ribosome in RNA complex. Subsequently we used the Xenopus oocyte system to study the involvement of adenylyl cyclase and G proteins in the induction of meiotic maturation. In more recent years our laboratory has been studying the structure, function, and regulations of two ubiquitous protein kinases CK1 and CK2, which are involved in the phosphorylation of many key cellular proteins.