Catalytic-activity fraction ( - Dynamic NPU Manual

Catalytic-activity fraction (


Chemical amount


Definition in words

Catalytic-activity of component B divided by catalytic-activity of system 1

Note 1: Component B is a catalytic component

Note 2: Component B can be an isoenzynes of all isoenzymes (system 1)

Note 3: System 1 is all isoenzymes of a particular “enzyme family”

Definition by equation

Systematic terms

Catalytic-activity fraction of component B in system 1

Result type

Rational scale
  • Value sets are positive numerical values
  • Algebraic operations are allowed (a=nb; a≠nb)
Numerical values from 0-∞


10-18, 10-15, 10-12, 10-9, 10-6, 10-3, 1 (one), etc.

Special rule(s) in the NPU syntax

The catalytic entities (component B and system 1) are  termed according to the International Enzyme Nomenclature (see Medical and metrological vocabulary).

Unit, one (1) is omitted in the NPU syntax

“Procedure” is stated in the specification to the kind-of-property in the NPU definition.

“Procedure” indicates that the measurement procedure must be stated somewhere else than the NPU code and there may be difficulties in comparing values for the same NPU code.


Ferard G, Dybkaer R, Fuentes-Arderiu X. Compendium of Terminology and Nomenclature of Properties in Clinical Laboratory Sciences : Recommendations 2016. 1 ed: Royal Society of Chemistry; 2016. 182 p. doi:10.1039/9781782622451.

Laboratory field



Clinical Chemistry

Generic abbreviated
NPU21544 ALP(P)—Alkaline phosphatase, bone type; = ? T
Full result NPU21544 Alkaline phosphatase(Plasma)—Alkaline phosphatase, bone type; catalytic-activity fraction = 0.45
Abbreviated result NPU21544 ALP(P)—Alkaline phosphatase, bone type; = 0.45
Written expression The catalytic-activity of Alkaline phosphatase, bone type divided by catalytic-activity of (all) Alkaline phosphatase from Mr. Smith’s plasma is [0.45].


NPU database, and

  • Kind-of-property

    • Nominal kind-of-property

    • Kind-of-quantity

      • Ordinal kind-of-quantity

      • Unitary kind-of-quantity

        • Rational unitary kind-of-quantity

          • Catalytic-activity fraction


  • Dybkaer R. Concept system on ‘quantity’: formation and terminology. Accredit Qual Assur. 2013;18(3):253-60.
  • Dybkaer R. ISO terminological analysis of the VIM3 concepts ‘quantity’ and ‘kind-of-quantity’. Metrologia. 2010;47(3):127-34.
Date Term Note
1996-01-01 Catalytic-activity fraction Term established
Date Notes


2019-06-04 Catalytic component B is an enzyme, defined by the international enzyme nomenclature (, and shall be used for catalytic-activity kinds-of-property. Proteins are defined and termed by UNIPROT ( and should not be used in relation to catalytic-activity kinds-of-property. Though there are overlaps between these two nomenclatures..

The enzyme and protein nomenclatures can have different terms for the same molecule.

  • ABC-type protein transporter (Enzyme nomenclature, identifier EC
  • Alpha-hemolysin (Protein nomenclature, UP identifier P09616).