TASK DEFINITION: In this task, you are given a sentence. You are expected to recognize the name of any form of chemical substances. Although there might be several correct answers, you need to write one of them.
PROBLEM: The dynamics of cobalamin utilization in L-1210 mouse leukemia cells: a model of cellular cobalamin metabolism.

SOLUTION: cobalamin

PROBLEM: The preventive effect of uncarboxylated osteocalcin against free fatty acid-induced endothelial apoptosis through the activation of phosphatidylinositol 3-kinase/Akt signaling pathway: Uncarboxylated osteocalcin and endothelial apoptosis.

SOLUTION: phosphatidylinositol

PROBLEM: Synaptotagmin 1 is required for vesicular Ca(2+) /H(+) -antiport activity.

SOLUTION:
Ca(2+)