Appeal No. 2001-1586 Page 4
Application No. 08/402,394
We reverse. In addition, we raise other issues for the examiner and appellants to
consider.
DISCUSSION
The formation of human insulin is described in Thim at page 2, lines 5-21 as
follows:
Human insulin consists of two peptide chains, the A-chain containing 21
amino acid residues and the B-chain containing 30 amino acid residues. The A-
and B-chain are joined together by two disulfide bridges connecting the cysteinyl
residue at A7 to B7 and A20 to B19, respectively. A third disulphide bridge is
formed between the cysteinyl residues A6 and A11.
Human insulin is produced in vivo in the pancreas in the form of
preproinsulin. Preproinsulin consists of a prepeptide of 24 amino acid residues
followed by proinsulin containing 86 amino acid residues in the configuration:
prepeptide-B-Arg-Arg-C-Lys-Arg-A in which C is the C-peptide of 31 amino acid
residues.
During excretion from the islet cells the prepeptide is cleaved off and
proinsulin then folds to a structure in which disulfide bridges are formed. The C-
peptide is then excised proteolytically to give mature human insulin.
The compound set forth in claim 33 on appeal is termed a “mini-proinsulin” by
appellants and is stated to be useful in preparing human insulin ArgB31 –OH (mono-Arg
insulin). Specification, page 1. This compound is also described in Grau ‘332. Id.
Further, the compound of claim 33 is stated to show insulin activity itself. Id. As seen
from claim 42 reproduced above, mono-Arg insulin can be prepared by simply treating
the compound of claim 33 with trypsin.3
Key in deciding the issues raised in all of the obviousness rejections before us for
review is determining whether the compound of claim 33 is novel and unobvious. If the
compound of claim 33 is novel and unobvious, all of the obviousness rejections fall
3 This again assumes the reference in claim 42(a) to A(1-31) is a typo.
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