A
PubMed search for "method for amylase activity spectrophotometry" brought up numerous hits, here are some. Pick one that looks good and get it or do the search and choose your own. If you have questions about the assay, I'm sure the board can help.
1: Dahot MU, Saboury AA, Moosavi-Movahedi AA.
Inhibition of beta-amylase activity by calcium, magnesium and zinc ions
determined by spectrophotometry and isothermal titration calorimetry.
J Enzyme Inhib Med Chem. 2004 Apr;19(2):157-60.
PMID: 15449730 [PubMed - in process]
2: Yasmineh WG, Chung MY, Caspers JI.
Determination of serum catalase activity on a centrifugal analyzer by an
NADP/NADPH coupled enzyme reaction system.
Clin Biochem. 1992 Feb;25(1):21-7.
PMID: 1551237 [PubMed - indexed for MEDLINE]
3: Soor SK, Hincke MT.
Microplate reader-based kinetic determination of alpha-amylase activity:
application to quantitation of secretion from rat parotid acini.
Anal Biochem. 1990 Jul;188(1):187-91.
PMID: 2171376 [PubMed - indexed for MEDLINE]
4: Sion JP, Laureys M, Gerlo E, Gorus F.
Detection of macroenzymes in serum by high-performance gel permeation
chromatography.
J Chromatogr. 1989 Nov 10;496(1):91-100.
PMID: 2592519 [PubMed - indexed for MEDLINE]
5: Satomura S, Sakata Y, Omichi K, Ikenaka T.
Alpha-amylase assay with use of a benzyl derivative of p-nitrophenyl
alpha-maltopentaoside, BG5P.
Clin Chim Acta. 1988 Jun 15;174(3):315-23.
PMID: 3134147 [PubMed - indexed for MEDLINE]
6: Rauscher E, Neumann U, Schaich E, von Bulow S, Wahlefeld AW.
Optimized conditions for determining activity concentration of alpha-amylase in
serum, with 1,4-alpha-D-4-nitrophenylmaltoheptaoside as substrate.
Clin Chem. 1985 Jan;31(1):14-9.
PMID: 3871178 [PubMed - indexed for MEDLINE]