Appeal No. 1997-0838
Application 08/235,238
Humans produce five lactate dehydrogenase (LDH) isozymes, LDH , LDH , LDH ,1 2 3
LDH , and LDH , which catalyze the same reaction, but differ in certain of their physical4 5
and/or chemical properties. Each isozyme is composed of four subunits which may be
heart muscle type (H), or skeletal muscle type (M), or both. For example, LDH is
1
composed of four H subunits, LDH , LDH and LDH are composed of various2 3 4
combinations of the H and M subunits, while LDH is composed of four M subunits.
5
According to appellant,
Each of organs has its own composition of the isozymes. For example,
LDH is present in a myocardium in the largest amount. Since LDH1 1
escapes from the myocardium into blood under a condition of a myocardial
infarction, a rise in serum LDH level can be diagnostic for such a disease.
1
(Specification, page 1).
In its broadest aspect, the invention is directed to selective determination of LDH in
1
human serum or plasma (using an assay for total LDH activity), wherein LDH , LDH , LDH2 3 4
and LDH , also present in the samples, are inhibited with a combination of "-chymotrypsin
5
and a protein denaturing agent.
Obviousness
Claims 1, 4 through 6, 10, 11, 13, 15 and 16 stand rejected as unpatentable over
Iatron, Selmeci and Sanford.
Iatron selectively measures residual LDH activity in human serum using a protein
1
denaturing agent (urea, thiourea, guanidine, etc.) in an alkaline buffer (pH 10-11) to
inactivate LDH , LDH , LDH , and LDH .2 3 4 5
3
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