PK3: a new chromosome enzyme marker for gene dosage studies in chromosome 15 imbalance.

Gene dosage studies yielded results consistent with the assignment of the locus for pyruvate kinase (PK3) to chromosome 15. The activity of seven cytoplasmic enzymes has been determined in fibroblast extracts from six trisomy 15 lines and 16 normal control lines. The fibroblast extracts from the trisomic patients had pyruvate kinase activity 57% higher than fibroblast extracts from control lines, while other enzyme activities were within the normal range of activity.