Differential expression of adenosine deaminase isozymes in acute leukemia

Abstract

Total adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) activities were measured in cell samples from 13 cases of de novo acute leukemia and from three cases of chronic myeloid leukemia in blast crisis (CMLBC). These cases could be separated into lymphoid and nonlymphoid types on the basis of enzyme activity, with two misclassifications. However, PNP activity added little or no discriminatory information. Analysis for expression of the various molecular weight (mol wt) ADA isozymes, ADA1 (40 Kd) and ADA2 (110 Kd), revealed that ADA2 was expressed exclusively in nonlymphoid cells whereas ADA1 was found in both lymphoid and nonlymphoid cell types. Identification of ADA2 divided these leukemia cases into lymphoid and nonlymphoid types with no misclassifications (P = .0002; Fisher's exact test). Acute nonlymphoblastic leukemia (ANLL) with a monocytic component tended to have a greater percentage of ADA2 than ANLL without a monocytic component. These studies suggest that ADA2 may be a novel biochemical marker for an immature nonlymphoid cell.

Plasma adenosine deaminase2, is a marker for human immunodeficiency virus‐1 seroconversion

“…These findings are consistent with prior reports in which no significant differences in total serum ADA 10,12,13] or ADA, specifically [9,11,141 isoenzyme is present in plasma from normal [9,11,14,15,18,19] as WellasHIVinfectedpatients [9,11,13,141, it is nearly absent from most human cells [21-241 and thus its source is puzzling. Furthermore, it is difficult to postulate a physiological role for ADA, since its K , (2 mM) [15,19] is several orders of magnitude higher than plasma adenosine concentrations (> 150 nM) [24,25].…”

A Novel Germline Mutation of ADA2 Gene in Two “Discordant” Homozygous Female Twins Affected by Adenosine Deaminase 2 Deficiency: Description of the Bone-Related Phenotype

“…While considering the above described multiple actions of Ada enzyme in different cellular and tissue contexts, no direct evidence for its biological role in bone and mineral metabolism exists. Ada2 protein is expressed primarily by monocytes and macrophages [ 15 , 16 ], the latter known to be the precursors of osteoclast cell. However, osteoclast is not the only bone cell in which Ada activity can play a pathophysiological role, since osteoblasts also express it.…”

Syzygium cumini inhibits adenosine deaminase activity and reduces glucose levels in hyperglycemic patients

“…ADA is present in serum and in most tissues and several ADA isozymes exist, with different tissue distribution. ADA2 is a major component of serum ADA activity, whereas the isoform 1 is predominant in erythrocytes [12][13][14][15].…”