

<!--P3XBRL-->
<!--version 4.1.21 -->
<!--http://www.p3xbrl.com-->
<!--produced on 2012-11-05 @ 12:38 PM-->
<xsd:schema targetNamespace="http://www.protalix.com/20120930" elementFormDefault="qualified" xmlns:plx="http://www.protalix.com/20120930" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:num="http://www.xbrl.org/dtr/type/numeric" xmlns:nonnum="http://www.xbrl.org/dtr/type/non-numeric" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <xsd:annotation>
    <xsd:appinfo>
      <link:linkbaseRef xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:href="plx-20120930_cal.xml" xlink:type="simple" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" />
      <link:linkbaseRef xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:href="plx-20120930_def.xml" xlink:type="simple" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" />
      <link:linkbaseRef xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:href="plx-20120930_lab.xml" xlink:type="simple" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" />
      <link:linkbaseRef xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:href="plx-20120930_pre.xml" xlink:type="simple" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" />
      <link:roleType roleURI="http://www.protalix.com/role/CondensedConsolidatedBalanceSheets" id="plx-ccbs" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>002 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/CondensedConsolidatedStatementsOfCashFlows" id="plx-cccf" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>007 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/CondensedConsolidatedStatementOfChangesInShareholdersEquityCapitalDeficiency" id="plx-ccse" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>005 - Statement - CONDENSED CONSOLIDATED STATEMENT OF CHANGES IN SHAREHOLDERS' EQUITY (CAPITAL DEFICIENCY)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/CondensedConsolidatedStatementOfChangesInShareholdersEquityCapitalDeficiencyParenthetical" id="plx-ccsep" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>006 - Statement - CONDENSED CONSOLIDATED STATEMENT OF CHANGES IN SHAREHOLDERS' EQUITY  (CAPITAL DEFICIENCY) (Parenthetical)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/CondensedConsolidatedStatementsOfOperations" id="plx-ccso" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>003 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/CondensedConsolidatedStatementsOfOperationsParenthetical" id="plx-ccsop" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>004 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/DocumentAndEntityInformation" id="plx-dein" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>001 - Document - Document and Entity Information</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/InventoriesDetails" id="plx-invd" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>40201 - Disclosure - INVENTORIES (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/Inventories" id="plx-invt" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>102 - Disclosure - INVENTORIES</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/InventoriesTables" id="plx-invtt" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>302 - Disclosure - INVENTORIES (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/SignificantAccountingPoliciesDetails" id="plx-sapd" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>40101 - Disclosure -  SIGNIFICANT ACCOUNTING POLICIES (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/SignificantAccountingPolicies" id="plx-sapo" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>101 - Disclosure - SIGNIFICANT ACCOUNTING POLICIES</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/SignificantAccountingPoliciesPolicy" id="plx-sapp" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>201 - Disclosure - SIGNIFICANT ACCOUNTING POLICIES (Policy)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/SignificantAccountingPolicesScheduleOfWeightedAverageNumberOfSharesOutstandingUsedToCalculateEarningsLossPerShareDetails" id="plx-sapt1" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>40102 - Disclosure -  SIGNIFICANT ACCOUNTING POLICIES (Schedule of Weighted Average Number of Shares Outstanding used to Calculate Earnings (Loss) per Share) (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/SignificantAccountingPoliciesTables" id="plx-sapt2" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>301 - Disclosure - SIGNIFICANT ACCOUNTING POLICIES (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/StockTransactionsDetails" id="plx-sttd" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>40301 - Disclosure - STOCK TRANSACTIONS (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/StockTransactions" id="plx-sttr" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>103 - Disclosure - STOCK TRANSACTIONS</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/SubsequentEvents" id="plx-suev" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>104 - Disclosure - SUBSEQUENT EVENTS</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.protalix.com/role/SubsequentEventsDetails" id="plx-suevd" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>40401 - Disclosure - SUBSEQUENT EVENTS (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:labelLink</link:usedOn>
        <link:usedOn>link:referenceLink</link:usedOn>
      </link:roleType>
    </xsd:appinfo>
  </xsd:annotation>
  <xsd:import namespace="http://xbrl.sec.gov/country/2012-01-31" schemaLocation="http://xbrl.sec.gov/country/2012/country-2012-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/currency/2012-01-31" schemaLocation="http://xbrl.sec.gov/currency/2012/currency-2012-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/dei/2012-01-31" schemaLocation="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/exch/2012-01-31" schemaLocation="http://xbrl.sec.gov/exch/2012/exch-2012-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/invest/2012-01-31" schemaLocation="http://xbrl.sec.gov/invest/2012/invest-2012-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/naics/2011-01-31" schemaLocation="http://xbrl.sec.gov/naics/2011/naics-2011-01-31.xsd" />
  <xsd:import namespace="http://www.xbrl.org/2009/role/negated" schemaLocation="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd" />
  <xsd:import namespace="http://www.xbrl.org/2009/role/net" schemaLocation="http://www.xbrl.org/lrr/role/net-2009-12-16.xsd" />
  <xsd:import namespace="http://www.xbrl.org/dtr/type/non-numeric" schemaLocation="http://www.xbrl.org/dtr/type/nonNumeric-2009-12-16.xsd" />
  <xsd:import namespace="http://www.xbrl.org/dtr/type/numeric" schemaLocation="http://www.xbrl.org/dtr/type/numeric-2009-12-16.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/sic/2011-01-31" schemaLocation="http://xbrl.sec.gov/sic/2011/sic-2011-01-31.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/stpr/2011-01-31" schemaLocation="http://xbrl.sec.gov/stpr/2011/stpr-2011-01-31.xsd" />
  <xsd:import namespace="http://fasb.org/us-gaap/2012-01-31" schemaLocation="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd" />
  <xsd:import namespace="http://fasb.org/us-types/2012-01-31" schemaLocation="http://xbrl.fasb.org/us-gaap/2012/elts/us-types-2012-01-31.xsd" />
  <xsd:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" />
  <xsd:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" />
  <xsd:import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" />
  <xsd:element name="CashlessExerciseOfStockOptions" id="plx_CashlessExerciseOfStockOptions" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element name="CollaborativeArrangementProfitSharePercentage" id="plx_CollaborativeArrangementProfitSharePercentage" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="num:percentItemType" />
  <xsd:element name="CostOfRevenuesMember" id="plx_CostOfRevenuesMember" nillable="true" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType" />
  <xsd:element name="DepreciationAmortizationAndAssetImpairment" id="plx_DepreciationAmortizationAndAssetImpairment" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element name="DocumentAndEntityInformationAbstract" id="plx_DocumentAndEntityInformationAbstract" nillable="true" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType" />
  <xsd:element name="EmployeeAndNonemployeeMember" id="plx_EmployeeAndNonemployeeMember" nillable="true" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType" />
  <xsd:element name="EmployeeMember" id="plx_EmployeeMember" nillable="true" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType" />
  <xsd:element name="EmployeesMember" id="plx_EmployeesMember" nillable="true" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType" />
  <xsd:element name="GrantsAndReimbursementsReceivedOrReceivable" id="plx_GrantsAndReimbursementsReceivedOrReceivable" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element name="IncreaseInLiabilitiesForPropertyPlantAndEquipment" id="plx_IncreaseInLiabilitiesForPropertyPlantAndEquipment" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element name="MilestonePayment" id="plx_MilestonePayment" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element name="NatureOfOperationsPolicyTextBlock" id="plx_NatureOfOperationsPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" />
  <xsd:element name="NumberOfSubsidiaries" id="plx_NumberOfSubsidiaries" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType" />
  <xsd:element name="OptionExerciseMember" id="plx_OptionExerciseMember" nillable="true" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType" />
  <xsd:element name="OtherGainsLosses" id="plx_OtherGainsLosses" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element name="PfizerIncorporationMember" id="plx_PfizerIncorporationMember" nillable="true" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType" />
  <xsd:element name="ProceedsFromIssuanceOfCommonStockNetOfExpenses" id="plx_ProceedsFromIssuanceOfCommonStockNetOfExpenses" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element name="ProtalixBioTherapeuticsIncorporationMember" id="plx_ProtalixBioTherapeuticsIncorporationMember" nillable="true" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType" />
  <xsd:element name="ResearchDevelopmentAndEngineeringExpenseNet" id="plx_ResearchDevelopmentAndEngineeringExpenseNet" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element name="ScenarioOneMember" id="plx_ScenarioOneMember" nillable="true" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType" />
  <xsd:element name="ScenarioTwoMember" id="plx_ScenarioTwoMember" nillable="true" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardGrantDateFairValue" id="plx_ShareBasedCompensationArrangementByShareBasedPaymentAwardGrantDateFairValue" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardGrantedContractualTerm" id="plx_ShareBasedCompensationArrangementByShareBasedPaymentAwardGrantedContractualTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:decimalItemType" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfInstallmentsForVestingPeriod" id="plx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfInstallmentsForVestingPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:decimalItemType" />
  <xsd:element name="SignificantAccountingPoliciesLineItems" id="plx_SignificantAccountingPoliciesLineItems" nillable="true" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType" />
  <xsd:element name="SignificantAccountingPoliciesTable" id="plx_SignificantAccountingPoliciesTable" nillable="true" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" />
  <xsd:element name="StockCompensationPlanAndRestrictedStockMember" id="plx_StockCompensationPlanAndRestrictedStockMember" nillable="true" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType" />
  <xsd:element name="StockOptionsAndRestrictedSharesMember" id="plx_StockOptionsAndRestrictedSharesMember" nillable="true" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType" />
  <xsd:element name="SupplementalOfferingAndStockIssuanceCosts" id="plx_SupplementalOfferingAndStockIssuanceCosts" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element name="WeightedAverageNumberBasicAndDilutedSharesOutstandingAbstract" id="plx_WeightedAverageNumberBasicAndDilutedSharesOutstandingAbstract" nillable="true" abstract="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType" />
</xsd:schema>