PerkinElmer

Enzymology

OF

Find the end-point and real-time kinetic reagents and instruments you need for your enzymatic assays. We offer:

  • Radiolabeled substrates for highly-sensitive kinetic assays and antibody-free screening
  • TR-FRET, TRF, and Alpha no-wash technologies for fast and simple measurement of biochemical and cellular enzymatic activity
  • Microfluidic mobility-shift assays (MSA) for radiometric analysis of substrate conversion, kinetics, and mechanism-of-action
  • Multi-mode plate readers for maximal speed and throughput independent of technology platform

  • Products and Services

  • Resources, Events & More

Narrow your results
Product Type
  • Consumables (2)
  • Instruments (1)
  • Reagents (270)
Antibody conjugates
  • Anti-acetyl-lysine (1)
  • Anti-Acetyl-Lysine (1)
  • Anti-H3 (C-term) (1)
  • Anti-H3K27ac (2)
  • Anti-H3K27me2 (1)
  • Anti-H3K27me2-1 (1)
  • Anti-H3K27me3 (2)
  • Anti-H3K36me2 (2)
  • Anti-H3K4 (3)
  • Anti-H3K4me1-2 (2)
  • Anti-H3K9/H3K27 (1)
  • Anti-H3K9/K27 (1)
  • Anti-H3K9ac (2)
  • Anti-H3K9me2 (2)
  • Anti-H3R2me (1)
  • Anti-H4K20me1 (1)
  • Anti-H4R3me (2)
  • Anti-methyl arginine (1)
  • Anti-methyl-Arg (1)
  • Anti-O-GlcNAc (1)
  • Anti-O-linked-GlcNAc (1)
  • Anti-P-PKA (1)
  • Anti-P-Ser (1)
  • Anti-P-Ser 14-3-3 (1)
  • Anti-P-Tyr-100 (1)
  • Anti-p53K382ac (2)
  • Anti-phospho-4EBP1 (1)
  • Anti-phospho-Acetyl-CoA-Carboxylase (1)
  • Anti-phospho-Crosstide (1)
  • Anti-phospho-glycogen synthase (1)
  • Anti-phospho-Histone H3 (2)
  • Anti-phospho-I?Ba (1)
  • Anti-phospho-MEK1/2 (1)
  • Anti-phospho-p70S6K (1)
  • Anti-phospho-PKC (1)
  • Anti-phospho-PLK (1)
  • Anti-phospho-rpS6 (1)
  • Anti-phospho-serine (2)
  • Anti-phospho-threonine (2)
  • Anti-phospho-Topo IIa (1)
  • Anti-phospho-Tyrosine Hydroxylase (1)
  • P-Tyr-100 (1)
  • PT66 (2)
  • PY20 (2)
  • Streptavidin/Phosphosensor (1)
  • Streptavidin/PT66 (1)
  • Streptavidin/PY20 (1)
Application
  • Drug Discovery & Development (3)
  • Epigenetics (47)
  • Kinase (139)
  • Multiplexing (6)
  • Protein Analysis & Detection (96)
Assay Points
  • 100 (29)
  • 1000 (1)
  • 10000 (79)
  • 500 (88)
  • 5000 (10)
  • 50000 (81)
Assay Target
  • 4EBP1 (3)
  • Akt1 (3)
  • Akt1/2 (1)
  • Akt1/2/3 (6)
  • ALK (2)
  • ATF1 (1)
  • ATF2 (1)
  • BAD (2)
  • c-Jun (2)
  • c-Met (1)
  • Caspase-9 (1)
  • Chk-1 (1)
  • Chk-2 (1)
  • Cofilin (1)
  • CREB (2)
  • EGFR (2)
  • eIF2α (1)
  • eIF4E (2)
  • Elk1 (1)
  • ErbB2 (1)
  • ERK1/2 (7)
  • GAPDH (1)
  • GSK3α (1)
  • GSK3β (5)
  • Histone H2A (1)
  • Histone H3 (11)
  • Hsp27 (1)
  • IGFR (1)
  • IKKα (3)
  • INSR (2)
  • IκBα (1)
  • JNK1/2/3 (5)
  • JNK1/3 (1)
  • MEK1 (5)
  • MKK3/6 (1)
  • MKK4 (1)
  • mTOR (5)
  • NFκB (3)
  • p38 MAPK (3)
  • p53 (2)
  • p70 S6K (4)
  • PDK1 (1)
  • S6RP (6)
  • SLP-76 (4)
  • SMAD1 (2)
  • SMAD2 (1)
  • SMAD3 (2)
  • STAT1 (1)
  • STAT3 (6)
  • STAT4 (1)
  • STAT5 (2)
  • Topo IIα (2)
  • VEGF2 Receptor (2)
  • β-Catenin (1)
Assay Target Class
  • Histone (11)
  • Phosphoprotein (106)
  • Protein (6)
Automation Compatible
  • Yes (214)
Detection Method
  • Alpha (151)
  • DELFIA TRF (6)
  • Fluorescence (1)
  • Radiometric (4)
  • Time-Resolved Fluorescence (TRF) (64)
  • TR-FRET (58)
Experimental type
  • In vitro (197)
Fluorophore
  • 5-FAM (31)
  • Eu-N1 (6)
  • Eu-W1024 (39)
  • FITC (3)
  • ULight (19)
Format
  • Microplates (215)
Molecular modification
  • Acetylation (12)
  • GlcNAc (1)
  • Glycosidation (1)
  • Methylation (26)
  • Phosphorylation (119)
  • Total (1)
  • Unmodified (4)
Product Brand Name
  • Alpha SureFire Ultra Multiplex (6)
  • AlphaLISA (32)
  • AlphaLISA SureFire Ultra (52)
  • AlphaPlex (7)
  • AlphaScreen (3)
  • AlphaScreen SureFire (60)
  • DELFIA (6)
  • LabChip® (1)
  • LANCE (7)
  • LANCE Ultra (51)
  • SPA Enzymatic Assays (3)
Radioisotope
  • H-3 (3)
Sample Volume
  • 2 mL (1)
  • 35 mL (1)
  • 400 mL (1)
Target Species
  • Human (107)
Therapeutic Area
  • Epigenetics (11)
Volume
  • 0-50 (92)
  • 51-100 (1)
  • 151-200 (3)
  • 201-250 (18)
  • 351-400 (1)
  • 451-500 (50)
  • Over 500 (50)

"Enzymology" 1-50 of 273 Products and Services

Sort
Per Page
LabChip EZ Reader

EZ READER, SHIP LEVEL

The EZ Reader can help to save time and money in your laboratory by identifying the most promising lead candidates faster.
AlphaLISA SureFire Ultra kits

AlphaLISA SureFire Ultra p-eIF4E (Ser209) Assay Kits

The AlphaLISA® SureFire® Ultra™ p-eIF4E(Ser209) assay is a sandwich immunoassay for quantitative detection of phospho-eIF4E (phosphorylated on Ser209) in cellular lysates using Alpha Technology.
Price Range : 475.00 USD - 27500.00 USD
AlphaLISA SureFire Ultra kits

AlphaLISA SureFire Ultra p-ERK1/2 (Thr202/Tyr204) Assay Kit

The AlphaLISA® SureFire® Ultra™ p-ERK 1/2 (Thr202/Tyr204) assay is a sandwich immunoassay for quantitative detection of phospho-ERK 1/2 (phosphorylated on Thr202/Tyr204 in ERK1, or Thr185/Tyr187 in ERK2) in cellular lysates using Alpha Technology.
Price Range : 475.00 USD - 27500.00 USD
PerkinElmer

PDE Substrate iFL-cGMP, for LabChip EZ Reader

Fluorescently-labelled cGMP for Phosphodiesterase Assays (Enyzme inhibiton, target discovery, lead optimization)
List Price : 721.00 USD

DELFIA Eu-N1 labeled anti-phosphoserine antibody, 10µg

Europium-labeled anti-phosphoserine antibody, for capturing antibodies in DELFIA® TRF kinase assays.
List Price : 1239.00 USD
PerkinElmer

ProfilerPro Kinase Peptide Substrate 13, for LabChip EZ Reader

Fluorescently-labelled peptide substrate 13 for kinase assays (inhibiton, target discovery, lead optimization)
List Price : 721.00 USD

DELFIA Eu-N1 Labeled Anti-Phosphothreonine Antibody, 10µg

Europium-labeled anti-phosphothreonine antibody, for use in DELFIA® time-resolved fluorescence (TRF) kinase assays.
List Price : 1246.00 USD

AlphaScreen PhosphoSensor Kit

Antibody-free assay for kinase activity via dectection of phosphorylated protein or peptide substrate.
Price Range : 349.00 USD - 2794.00 USD
PerkinElmer

ProfilerPro Kinase Peptide Substrate 11, for LabChip EZ Reader

Fluorescently-labelled peptide substrate 11 for kinase assays (inhibiton, target discovery, lead optimization)
List Price : 721.00 USD
AlphaLISA Cellular Epigenetics kits

AlphaLISA Acetylated-Histone H3 Lysine 27 (H3K27ac) Cellular Detection Kit

This kit is designed for the detection of acetylated Histone H3 Lysine 27 (H3K27ac) in cell lysates using a homogeneous AlphaLISA assay (no wash steps).
Price Range : 675.00 USD - 12000.00 USD

LANCE Ultra ULight™-CREBtide

CREBtide peptide (sequence: CKRREILSRRPSYRK) labeled with ULight™ dye. Synthetic peptide derived from human cAMP Response Element Binding (CREB) Protein (phosphorylation site: Ser133). CREB (Ser 133) can be phosphorylated by a variety of kinases including MSK1, PKA and PKC isoforms.
Price Range : 231.00 USD - 838.00 USD

AlphaLISA Anti-acetyl-Histone H3 Lysine 27 (H3K27ac) Acceptor Beads

AlphaLISA® Acceptor beads conjugated to an antibody against human histone H3 acetylated at lysine 27 (H3K27ac). These beads can be used for no-wash AlphaLISA epigenetic writer and eraser assays.
Price Range : 1379.00 USD - 25100.00 USD
SureFire principle

AlphaScreen SureFire Phospho-MEK 1 Kit

The AlphaScreen® SureFire® p-MEK1 (Ser218/222) assay is a sandwich immunoassay for quantitative detection of phospho-MEK1 (phosphorylated on Ser218/222) in cellular lysates using Alpha Technology.
Price Range : 1449.00 USD - 15700.00 USD

DELFIA Eu-N1 Anti-Phosphtyrosine (P-Tyr-100)

Europium-labeled anti-phosphotyrosine (P-Tyr-100) antibody, for use in DELFIA® time-resolved fluorescence (TRF) kinase assays, phosphoprotein detection, and phosphoprotein binding assays.
Price Range : 234.00 USD - 3143.00 USD
AlphaLISA SureFire Ultra kits

AlphaLISA SureFire Ultra AKT 1/2/3 (pS473) Assay Kit

The AlphaLISA® SureFire® Ultra p-AKT1/2/3 (Ser473) assay is a sandwich immunoassay for quantitative detection of phospho-AKT1/2/3 (phosphorylated on Ser473) in cellular lysates using Alpha Technology.
Price Range : 475.00 USD - 27500.00 USD

Anti-methyl-Histone H3 Lysine 4 (H3K4me1-2) AlphaLISA Acceptor Beads

AlphaLISA® Acceptor beads conjugated to an antibody against human histone H3 mono- or di-methylated at lysine 4 (H3K4me1-2). These beads can be used for no-wash AlphaLISA epigenetic writer and eraser assays.
Price Range : 1379.00 USD - 25100.00 USD
PerkinElmer

LANCE Ultra ULight™-Tyrosine Hydroxylase (Ser40) peptide

ULight™-labeled synthetic peptide containing the amino acid residues surrounding Ser40 of tyrosine hydoxylase. The ULight-tyrosine hydroxylase peptide can be phosphorylated at Ser40 by a variety of kinases including Aurora A, PAK2, MSK1, PKA and PKC. Peptide core motif : RRQSLIE
Price Range : 298.00 USD - 813.00 USD
PerkinElmer

LANCE Ultra ULight-p70 S6K (Thr389) Peptide

ULight™-labeled synthetic peptide containing the amino acid residues surrounding Thr389 of human p70 S6K. The ULight-p70 S6K peptide can be phosphorylated at Thr389 by several kinases including mTOR, COT, HGK, IKKε, IRAK1, IRAK4, MAP4K2, MINK, MST1, MST2, NEK1, NEK2, NEK6, NEK7, PEK, PLK1, and TAOK2. Phosphorylation motif: LGFTYVAP
Price Range : 285.00 USD - 1164.00 USD

Anti-acetyl-Histone H3 Lysine 9 (H3K9ac) AlphaLISA® Acceptor Beads

AlphaLISA® Acceptor beads conjugated to an antibody against human histone H3 acetylated at lysine 9 (H3K9Ac). These beads can be used for no-wash AlphaLISA epigenetic writer and eraser assays.
Price Range : 1435.00 USD - 26100.00 USD
AlphaLISA SureFire Ultra kits

AlphaLISA SureFire Ultra p-SMAD3 (Ser423/425) Assay Kit

The AlphaLISA® SureFire® Ultra p-SMAD3 (Ser423/Ser425) assay is a sandwich immunoassay for quantitative detection of phospho-SMAD3 (phosphorylated on Ser423/Ser425) in cellular lysates using Alpha Technology.
Price Range : 475.00 USD - 27500.00 USD
SureFire principle

AlphaScreen SureFire IKKa (p-Ser176/Ser180) Assay Kit

The AlphaScreen® SureFire® p-IKKα (Ser176/180) assay is a sandwich immunoassay for quantitative detection of phospho-IKKα (phosphorylated on Ser176/180) in cellular lysates using Alpha Technology.
Price Range : 1590.00 USD - 17200.00 USD

LANCE® Eu-W1024 phospho-(Ser) 14-3-3 binding motif antibody, 10 µg

Europium-labeled anti-phospho-(Ser) 14-3-3 motif antibody, for use in LANCE® TR-FRET kinase assays.
List Price : 3300.00 USD

LANCE Ultra ULight™-IkappaB-alpha (Ser32/36) peptide

ULight™-labeled synthetic peptide containing the amino acid residues surrounding Ser32/36 of human IkappaB-alpha. The ULight-IkappaB-alpha peptide can be phosphorylated at Ser 32/36 by the IKKβ kinase. Peptide core motif: RHDSGLDSM
Price Range : 298.00 USD - 813.00 USD

Anti-methyl-Histone H3/H4 Arginine (H3/H4Rme pan) AlphaLISA Acceptor Beads

AlphaLISA® Acceptor beads conjugated to an antibody against human Histone H3 and H4 methylated on arginine residues. This bead can be used to create AlphaLISA no-wash epigenetic writer and eraser assays.
Price Range : 1379.00 USD - 25100.00 USD
AlphaLISA SureFire Ultra kits

AlphaLISA SureFire Ultra p-CREB (Ser133) Assay Kit

The AlphaLISA® SureFire® Ultra™ p-CREB (Ser133) assay is a sandwich immunoassay for quantitative detection of phospho-CREB (phosphorylated on Ser133) in cellular lysates using Alpha Technology.
Price Range : 475.00 USD - 27500.00 USD
PerkinElmer

LANCE Ultra Europium-anti-phospho-Myelin Basic Protein (MBP)

Mouse monoclonal antibody labeled with the LANCE® Eu-W1024-ITC chelate. This antibody recognizes specifically phosphorylated Thr232 in myelin basic protein (MBP; Swiss-Prot: P02686). MBP can be phosphorylated by a variety of kinases including Erk1/Erk2. Sequence motif recognized: FFKNIVTPRpTPPPSQGK
Price Range : 285.00 USD - 5800.00 USD
SureFire principle

AlphaScreen SureFire JNK 1-3 (p-Thr183;Tyr185) Assay Kit

The AlphaScreen® SureFire® p-JNK1/3 (Thr183/Tyr185) assay is a sandwich immunoassay for quantitative detection of phospho-JNK1/3 (phosphorylated on Thr183/Tyr185) in cellular lysates using Alpha Technology.
Price Range : 1449.00 USD - 15700.00 USD

LANCE Ultra Europium-anti-unmodified Histone H3 Lysine 9/Lysine 27 (H3K9/K27) Antibody

Europium-labeled monoclonal antibody recognizing human Histone H3 that is unmodified at lysine 9 and lysine 27 (H3K9/K27). For use in LANCE® Ultra epigenetic writer and eraser assays.
Price Range : 3383.00 USD - 8500.00 USD
SureFire principle

AlphaScreen SureFire Phospho-beta catenin (Ser45) Assay Kit

The AlphaScreen® SureFire® p-beta catenin (Ser45) assay is a sandwich immunoassay for quantitative detection of phospho-beta catenin (phosphorylated on Ser45) in cellular lysates using Alpha Technology.
Price Range : 1449.00 USD - 15700.00 USD
AlphaLISA SureFire Ultra kits

AlphaLISA SureFire Ultra Total Akt1 Assay Kit

The AlphaLISA® SureFire® Ultra™ Total Akt1 assay is a sandwich immunoassay for quantitative detection of Akt1 (both phosphorylated and non-phosphorylated) in cellular lysates using Alpha Technology. This assay is intended to be used as a normalization for phosphorylation studies.
Price Range : 475.00 USD - 27500.00 USD
AlphaLISA Cellular Epigenetics kits

AlphaLISA unmodified Histone H3 Lysine 4 (H3K4) Cellular Detection Kit

This kit is designed to be used as a control for the AlphaLISA Epigenetic Cellular Detection Kits, through detection of unmodified Histone H3 Lysine 4 (H3K4) in cell lysates using a homogeneous AlphaLISA assay (no wash steps).
Price Range : 675.00 USD - 12000.00 USD
AlphaLISA Cellular Epigenetics kits

AlphaLISA Human Total Histone H2A Cell-based Assay Kit

AlphaLISA no-wash assay kit for the detection of total human Histone 2A (H2A) in cell extracts or cells in culture medium.
Price Range : 717.00 USD - 13400.00 USD

LANCE Ultra ULight™-poly GT

Poly Glu-Tyr (4:1) labeled with ULightTM dye. This random polymer is a Tyrosine kinase substrate.
Price Range : 307.00 USD - 838.00 USD
SureFire principle

AlphaScreen SureFire Phospho-GSK 3b (Ser9) Kit

The AlphaScreen® SureFire® p-GSK 3β (Ser9) assay is a sandwich immunoassay for quantitative detection of phospho-GSK3β (phosphorylated on Ser9) in cellular lysates using Alpha Technology.
Price Range : 1449.00 USD - 15700.00 USD
SureFire principle

AlphaScreen SureFire mTOR (p-Ser2448) Assay Kit

The AlphaScreen® SureFire® p-mTOR (Ser2448) assay is a sandwich immunoassay for quantitative detection of phospho-mTOR (phosphorylated on Ser2448) in cellular lysates using Alpha Technology.
Price Range : 1449.00 USD - 15700.00 USD

Anti-methyl-Histone H3 Lysine 9 (H3K9me2) AlphaLISA Acceptor Beads

AlphaLISA® Acceptor beads conjugated to an antibody against human histone H3 di-methylated at lysine 9 (H3K9me2). These beads can be used for no-wash AlphaLISA epigenetic writer and eraser assays.
Price Range : 1379.00 USD - 25100.00 USD
AlphaLISA SureFire Ultra kits

AlphaLISA SureFire Ultra p-mTOR (Ser2448) Assay Kit, 500 Assay Points

The AlphaLISA® SureFire® Ultra™ p-mTOR (Ser2448) assay is a sandwich immunoassay for quantitative detection of phospho-mTOR (phosphorylated on Ser2448) in cellular lysates using Alpha no-wash technology.
List Price : 1605.00 USD

Anti-Histone H3 (C-term) AlphaLISA Acceptor Beads

AlphaLISA® Acceptor beads designed to capture Histone H3 in a homogeneous AlphaLISA assay for DOT1L. Use in conjunction with biotinylated anti-H3K79me2 (AL148).
Price Range : 1379.00 USD - 25100.00 USD
PerkinElmer

LANCE Ultra Europium-anti-phospho-p70 S6K (Thr389) Antibody

Mouse monoclonal antibody labeled with the LANCE® Europium W-1024-ITC chelate. This antibody detects human p70 S6K phosphorylated at Thr389. p70 S6K is phosphorylated in vivo by mTOR. p70 S6K peptides are also phosphorylated by several kinases including COT, HGK, IKKε, IRAK1, IRAK4, MAP4K2, MINK, MST1, MST2, NEK1, NEK2, NEK6, NEK7, PEK, PLK1 and TAOK2. Sequence motif recognized: LGFTYVAP
Price Range : 1488.00 USD - 6800.00 USD
Alpha SureFire Ultra Multiplex kits

Alpha SureFire Ultra Multiplex p-AKT(Ser473) (Eu) + p-ERK (Tb) Kit

The Alpha SureFire® Ultra Multiplex kits allow the rapid, sensitive, and quantitative detection of phosphoproteins from cells, combined with the measurement of another protein, phospho or total. This Alpha Multiplex measurement is carried out in the same assay plate well from a single sample of cell lysate, and is achieved by the use of two types of Alpha Acceptor beads that emit at distinct wavelengths (545nm and 615nm).
Price Range : 855.00 USD - 49600.00 USD
PerkinElmer

LANCE Ultra Europium anti-phospho-Glycogen Synthase (Ser641)

Europium-labeled rabbit polyclonal antibody recognizing human Muscle Glycogen Synthase phosphorylated at Ser641. Antibody labeled with the LANCE® Eu-W1024-ITC chelate. Sequence motif recognized: PApSVPPSPSL
Price Range : 1984.00 USD - 6900.00 USD

LANCE Ultra ULight™-poly GAT

Poly Glu-Ala-Tyr (1:1:1) labeled with ULight™ dye. This random polymer is a Tyrosine kinase substrate.
Price Range : 322.00 USD - 930.00 USD
AlphaLISA SureFire Ultra kits

AlphaLISA SureFire Ultra p-Ribosomal Protein S6 (Ser240/244) HV Assay Kit, 100 Assay Points

The AlphaLISA® SureFire® Ultra™ p-rpS6 (Ser240/244) assay is a sandwich immunoassay for quantitative detection of phospho-Ribosomal Protein S6 (phosphorylated on Ser240/244) in cellular lysates using Alpha no-wash technology.
List Price : 475.00 USD

AlphaLISA Biotin-anti-Histone H4 Antibody

AlphaLISA® biotinylated monoclonal antibody recognizing the amino-terminal end of human histone H4. Broad species cross-reactivity is expected based on sequence similarity. This product is designed to be used with AlphaLISA® Epigenetics Acceptor beads to detect modified full-length histone H4 in homogeneous AlphaLISA assays.
Price Range : 1075.00 USD - 9700.00 USD
SureFire principle

AlphaScreen SureFire EGFR (p-Tyr1068) Assay Kit

The AlphaScreen® SureFire® p-EGFR (Tyr1068) assay is a sandwich immunoassay for quantitative detection of phospho-EGFR (phosphorylated on Tyr1068) in cellular lysates using Alpha Technology.
Price Range : 1590.00 USD - 17200.00 USD

LANCE Ultra ULight-Glycogen Synthase (Ser641/pSer657) Peptide

Glycogen synthase peptide (Sequence: PASVPPSPSLSRHSSPHQ(pS)ED) labeled with ULight™ dye. Synthetic peptide containing residues surrounding Ser641 and Ser657 of human Muscle Glycogen Synthase. This peptide is pre-phosphorylated on Ser657. Target phosphorylation site: Ser641. This peptide substrate can be phosphorylated by a variety of kinases including GSK3α and GSK3β.
Price Range : 381.00 USD - 837.00 USD
AlphaLISA SureFire Ultra kits

AlphaLISA SureFire Ultra p-eIF2α (Ser51) Assay Kit

The AlphaLISA® SureFire® Ultra™ p-eIF2α (Ser51) assay is a sandwich immunoassay for quantitative detection of phospho-eIF2α (phosphorylated on Ser51) in cellular lysates using Alpha Technology.
Price Range : 475.00 USD - 27500.00 USD
PerkinElmer

ProfilerPro Kinase Peptide Substrate 16, for LabChip EZ Reader

Fluorescently-labelled peptide substrate 16 for kinase assays (inhibiton, target discovery, lead optimization)
List Price : 721.00 USD

LANCE Ultra Europium-anti-phospho-PLK (Ser137) antibody

Affinity-purified rabbit polyclonal antibody labeled with the LANCE® Europium W-1024-ITC chelate. This antibody detects peptides derived from polo-like kinase (PLK) and phosphorylated at serine 137. PLK (Ser137) peptides can be phosphorylated by a variety of kinases including Aurora A, PAK2, MSK1, PKA and PKC. Sequence motif recognized: RRRSLLE
Price Range : 1488.00 USD - 6800.00 USD

"Enzymology" 1-50 of 273 Products and Services

Per Page