抄録
The stability of various enzymes in commercially available control sera was tested for suitability for use as standard materials and results showed a temperature-dependent increase in alkaline phosphatase (AL-P) activity in reconstituted lyophilized sera and a cold lability of LDH at 4°. Results obtained from further studies on the properties of AL-P and LDH in the reconstituted control sera were as follows;
1) Heterogeneity of AL-P isozymes in control sera gives the difficulty for standardizing the determination of AL-P activity.
2) Undialyzable substances other than albumin increase AL-P activity during storage. AL-P activity decreases with time when bovine serum albumin is added to the enzyme solution but is stabilized when human serum albumin added.
3) Treatment with lipoprotein lipase quenches a temperature-dependent increase in AL-P activity in reconstituted lyophilized sera. Desialidation, however, does not change the activity during storage.
4) Cold lability of LDH at 4° is observed in some control sera, in which contain LDH-4 and LDH-5 as the components of LDH.
